Archive of changes made to the dtbook3 DTD during its evolution through
Version 3-12.

This file: dtbk3-dtd-changes.txt

Version 3-12, as it evolved. by Harvey Bingham
        1999-01-23 revision 3-01
        1999-06-25 revision 3-02
        1999-07-20 revision 3-03
        1999-09-16 revision 3-04
        1999-09-24 revision 3-05
        1999-11-05 revision 3-06
        2001-01-31 revision 3-07
        2001-03-08 revision 3-08
        2001-03-30 revision 3-09 basis for dtbook100.dtd
        2001-09-07 revision 3-10 version 1.0.0 first draft
        2001-09-21 revision 3-11 version 1.0.0 second draft
        2001-09-26 revision 3-12 V1.0.0 third draft

    The history of changes prior to this version, including those
    in internal drafts through dtbk3-10.dtd and before is in:

        http://www.loc.gov/nls/z3986/background/dtbk3-dtd-changes.txt

    In that directory also are the old dtdbk3 dtds and their documentation.


============================================================================

Extracted from the public release of version 3-06 by Harvey Bingham
while preparing Version 7.

2000-01-31

<!--HB: 1999-11-05 drama module added conditional controls. -->
<!--HB: 1999-11-05 conditional section including drama module. -->
<!--HB: 1999-01-23 Renamed note to notice and footnote to note. -->
<!--HB: 1999-11-05 % dtbook3block put this second
    definition in conditional section, controlled by %ignore-drama; -->
<!--HB: 2001-01-19 % dtbook3block content excludes drama if %drama;
    is not already defined by including the conditional section
    that adds the drama module. The first declaration to occur
    is used. So if the conditional section of a book needing
    drama markup changes %include-drama; to INCLUDE, the following 
    declaration of % drama as empty is ignored. Also eliminated
    the separate conditional section around the definition of
    % dtbook3block. (See later conditional section for actual
    elements of the drama module.)
-->
<!--HB: 1999-01-23 Added %inlineinblock; a subset of %inline;
    for use as block elements without surrounding block parent. -->
<!--HB: 1999-09-16 Added citation, omitted reference above about
    inline version of prodnote. Note there is no way to inject
    #PCDATA in this use. -->
<!--HB: 1999-09-16 events in HTML 4.0 deal with click, mouse, or
    key actions. Events are ignored in dtbook3. -->
<!--HB: 1999-01-23 Changed from use of attrs to make id required -->
<!--HB: 1999-06-25 book: made bodymatter optional. -->
<!--HB: 1999-06-25 frontmatter: added required initial doctitle,
    clarified in Use that for any kinds of information with levels,
    level1 is appropriate instead of div. -->
<!--HB: 1999-09-16 frontmatter: Added level to allow recursive levels
    in place of the explicitly nested level1, level2, ... level6 and the
    use of recursive div and hd for deeper levels of nesting. -->
<!--HB: 1999-09-16 bodymatter: added level to allow recursive levels
    in place of the explicitly nested level1, level2, ... level6 and
    the use of recursive div and hd for deeper levels of nesting. -->
<!--HB: 1999-09-16 rearmatter: added level to allow recursive levels
    in place of the explicitly nested level1, level2, ... level6 and
    the use of recursive div and hd for deeper levels of nesting. -->
<!--HB: 1999-09-16 level: Added level to allow recursive levels in place
    of the explicitly nested level1, level2, ... level6 and the use of
    recursive div and hd for deeper levels of nesting. -->
<!--HB: 1999-11-05 level: Revised Use e.g., part, chapter, letter. -->
<!--HB: attlist level has a depth attribute, with values 1, 2, ... 
    indicating the depth of nesting. The highest level is 1, analogous
    to level1. As depth can be determined for any book by 
    algorithm, its value is not required. When omitted, reuse of
    material in larger compilations that have their own higher levels
    may be possible if no reuse of id values occurs. -->
<!--HB: 1999-09-16 level1: augmented use description of level 1 to indicate 
    alternative use of recursive level instead. -->
<!--HB: 1999-11-05 level1: revised use. -->
<!--HB: 1999-11-05 level2: revised use e.g., to exclude letter. -->
<!--HB: 1999-11-05 level3: revised use e.g., part, chapter, letter. -->
<!--HB: 1999-11-05 level4: revised use e.g., part, chapter, letter. -->
<!--HB: 1999-11-05 level5: revised use e.g., part, chapter, letter. -->
<!--HB: 1999-11-05 level6: revised use e.g., part, chapter, letter. -->
<!--HB: 1999-01-23 Renamed cite to citation. -->
<!--HB: 1999-09-16 Added linenum to %special; -->
<!--HB: 1999-09-16 Added linenum to %speciala; -->
<!--HB: 1999-01-23 Renamed fnref to noteref, added prodinl as
    inline rather than need to use the block form, prodnote. -->
<!--HB: 1999-09-16 Replaced prodinl by prodnote, with the 
    expectation that when used in an inline context it does
    not inject block elements. -->
<!--HB: 1999-09-24 changed s to sent to avoid conflict with HTML s. -->
<!--HB: 1999-09-16 Replaced prodinl by prodnote, with the 
    expectation that when used in an inline context it does
    not inject block elements -->
<!--HB: 2001-01-19 Changed comment s to sent -->
<!--HB: 1999-01-23 Renamed fnref to noteref
    added prodinl as inline version of prodnote. -->
<!--HB: 1999-09-16 dropped prodnote as inappropriate within table cell. -->
<!--HB: 1999-09-24 changed s to sent to avoid conflict with HTML s. -->
<!--HB: 1999-09-16 dropped prodnote to avoid duplication, as already
    in %block; where used to define % flow. -->
<!--HB: 1999-09-24 changed s to sent to avoid conflict with HTML s. -->
<!--HB: 1999-09-24 Changed % flow to removed prodnote from the former 
     %inline;, as already in %block; -->
<!--HB: 1999-09-16 linenum generalized to occur where br can. -->
<!--HB: 1999-06-25 div: made content model consistent with levelN 
    and expanded comments to allow recursive divs to any level. -->
<!--HB: 1999-09-16 div: replaced the use of div as recursive container
    by level, the explicitly recursive element, with nesting depth 
    indicated by the implied depth attribute. Removed hd element
    from content model. -->
<!--HB: 1999-01-23 Changed name from note to notice. -->
<!--HB: 1999-09-16 prodnote can occur inline. In such use, it should
    contain inline material, not injecting block tags that might
    distort the inline context where it occurs. --> 
<!--HB: 1999-01-23 sidebar: changed description to refer to note, not
    footnote, and noteref rather than fnref. -->
<!--HB: 1999-06-25 sidebar: changed description to refer to pagenum,
    not pgnum. -->
<!--HB: 1999-01-23 Generalized from footnote to allow any
    out-of-line material other than sidebar. It is not expected to be
    a container for table, object, or img, though they are allowed. -->
<!--HB: 1999-06-25 note: content model made repeatable to allow multiple
    block elements, such as paragraphs or lists. -->
<!--HB: 1999-09-16 note can contain citation through %inlineinblock; -->
<!--HB: 1999-06-25 note: comment changed replacing 'url' by
    'idref' with CDATA content that would allow it to contain a URL.
    Caution: this can inject semantic confusion, where IDREF in XML
    is only allowed to contain name characters, so could not include
    the local prefix of a URL: "source#localid". Since most noterefs will
    be into the current document, the source is omissible, and the localid
    is indicated by the "#" prefix. The prefix "#" could be omitted if
    only internal references were allowed, and if the more restricted
    XML idref attribute type IDREF were used. -->
<!--HB: 1999-01-23 note: Changed to make id attribute required. The id
    values need to be unique across all external entities that
    comprise the book. -->
<!--HB: Moved linenum into %inline, omit from lin -->
<!--HB: 1999-01-23 Renamed cite to citation. -->
<!--HB: 1999-07-15 abbr clarified use. -->
<!--HB: 1999-09-24 added comma to Use: text. -->
<!--HB: 1999-07-15 acronym clarified use. -->
<!--HB: 1999-01-23 Renamed cite to citation. -->
<!--HB: 1999-06-25 acronym: added attribute
    pronounce (yes | no) #IMPLIED. -->
<!--HB: 1999-01-23 Changed comment from fnref to noteref. -->
<!--HB: 1999-09-24 changed s to sent to avoid conflict with HTML s. -->
<!--HB: 1999-01-23 Changed the page attribute "regular" to "normal". -->
<!--HB: 1999-01-23 Renamed fnref to noteref -->
<!--HB: 1999-01-23 Renamed fnref to noteref, and attributes:
    Renamed attribute footnote to idref, it is a reference to material
    in this book, Changed IDREF declared value to CDATA, to allow
    noterefs via URL instead, useful when the book has disjoint parts.
    Added attribute type, with value typically "source" or "explanatory".
    Eliminated symbol as it is part of content in the book. -->
<!--HB: 1998-06-25 p: added %list; and dl inside p. This models the
enclosing paragraph that has subsidiary lists. This is inconsistent
with the HTML 4.0 DTD.-->
<!--HB: 1999-06-25 doctitle: element added as required first element of
    frontmatter. -->
<!--HB: 1999-09-16 levelhd added to provide header for recursive level. -->
<!--HB: 1999-06-25 hd: expanded description about use with div. -->
<!--HB: 1999-09-16 hd: eliminated description of use with div. -->
<!--HB: 1999-06-25 doctitle: attributes added for new element. -->
<!--HB: 1999-09-24 levelhd: attributes added for new element. -->
<!--HB: 2001-01-19 levelhd: added depth attribute. The depth value
    may be inferred by the depth of nesting of recursive levels,
    so is optional. Its presence may be a bar to reusing a level
    by injecting that level into a new higher compilation of level. 
    If both level and levelhd have depth specified, they should
    have the same depth value. -->
<!--HB: 1999-06-25 dl: added pagenum for cases where pagebreak occurs
    between definition list terms or definitions. As an inline,
    pagenum can still occur within either dt or dd. The text below
    in Use is extended to identify expected order, how to
    nest definitions, and placement of pagenum. -->
<!--HB: 1999-06-25 ol: added pagenum for cases where pagebreak occurs
    between list items, within which pagenum can occur as an inline. -->
<!--HB: 1999-06-25 ul: added pagenum for cases where pagebreak occurs
    between list items, within which pagenum can occur as an inline. -->
<!--HB: 1999-01-23 Caption can contain the pagenum for the start of
    a table at the top of a page. For a multi-page table, no pagenum
    should occur otherwise in the table. -->
<!--HB: 1999-06-25 Removed unused parameter entity head.content. -->
<!--HB: 1999-06-25 title: extended comment to differentiate title from
    doctitle. -->
<!--HB: 1999-06-25 meta: added comment describing Dublin Core from
    long dtbook3 version. -->

============================================================================
<!-- hb changes versions 3-07 through 3-09
 
    2001-01-31 revision 3-07
 
       1. Updated version number to 3-07.
 
       2. Moved prior changes to change history file:
 
          "http://www.loc.gov/nls/niso/chgs0106.txt"
 
       3. externalblock may gain content from the book
          internal subset, to enable addition of block-level
          element types:
          for examples,
              <!ENTITY % externalblock "| drama" >
          or if both drama and play were needed:
              <!ENTITY % externalblock "| drama | poem" >
 
       4. externalinline may augment the inlines used in the
          book, if in the book internal subset a different value
          is assigned to it, representing the inlines needed by
          the module or modules included in that internal subset.
          For example a book needing action concurrent with a
          speech, with content model %inline; might include in
          the parameter entity of the internal subset of the book:
              <!ENTITY % externalinline "| action" >
 
       5. % list content replaced ul and ol by list. Remains
          a parameter entity, so can be extended in book
          internal subset if desired.
 
       6. % dtbook3block added %externalblock; to allow extension
          of other block element types as needed by external
          module or modules.
 
       7. % inlineinblock Added <imgcaption> to contain and
          associate with <img> its caption.
 
       8. events attribute from HTML 4.0 is left empty,
          but could be added in book internal subset.
 
       9. showin attribute for text elements added to permit
          identification of the kinds of display appropriate
          for the element, so choice of presentation by the
          reader among alternative readings can be provided,
          when appropriate. Values of showin are:
 
              Braille Large Print
          code        print
          xxx                    hide
          xxp                 p  print only
          xls           l        large print only
          xlp           l     p  largeprint and print
          bxx   b                braille only
          bxp   b             p  braille and print
          blx   b       l        braille and largeprint
          blp   b       l     p  braille, largeprint, and print
 
          The default value is blp.
 
      10. prodnote added imgref attribute to associate
          the prodnote with one or more images.
 
      11. sidebar added hd to content model.
 
      12. poem eliminated, and its sub-elements author,
          linegroup, lin. If poem is needed, bring in
          poem module through book internal subset.
 
      13. drama eliminated and its sub-elements act,
          scene, stage, speaker, speech.  If drama is
          needed, bring in through book internal subset.
 
      14. line changed name of <lin> to line, made it generally
          available, such as in law text, not limited to poem.
 
      15. img Added to Use: mention of description using
          <imgcaption>. Also that id is needed when referenced
          by <imgcaption imgref="#yyy">.
 
      16. imggroup element added to contain <img> and its
          associated <imgcaption> and <prodnote>. Content
          model allows multiple <img> if they share a caption,
          multiple <imgcaption> if several captions refer to
          a single <img>, and multiple <prodnote> if different
          versions are needed for different media.
 
      17. imgcaption contains any printed caption that
          identifies one or more <img>. Associate <imgcaption>
          with each particular <img> by the imgref attribute
          value referencing each of the id values of the <img>s.
          The <imgcaption> may amplify or repeat the alt
          attribute string content on the <img>.
 
      18. hd Use is revised to remove drama and poem references.
 
      19. hd eliminated attribute level (or depth), as the
          hd list container indicates that information if needed.
 
      20. blockquote Repaired content model to put #PCDATA first.
          Eliminated %inlineinquote; Note a <blockquote> may
          contain many subsidiary blocks.
 
      21. list Replaced ol and ul, added attributes, and
          extended content model to allow heading <hd> and
          <prodnote>.
 
      22. List attributes may indicate the list kind.
          Presence of these attributes can help alternative
          assistive technology reconstruct the list original use.
              class (part of %attrs;) can describe unusual lists,
                  such as table of contents, list of figures,
                  or list of tables. For these, special
                  stylesheet treatment is appropriate.
              type
                  "ul" unordered list,
                  "ol" ordered list for which enum indicates form
              enum  enumeration in ordered list: enum values:
                  "1" numeric
                  "a" lower case alphabetic
                  "A" upper case alphabetic
                  "i" lower case roman
                  "I" upper case roman
              bullet  character or description of image used
                      for unordered list item prefix
 
      23. lic is a list item component within a <li>.
 
      24. link moved from elsewhere in DTD to section on
          Document Head where it is only used.
 
      25. meta removed reference to Dublin Core.
          Most metadata about a book is available in
          the package file.
 
      26. Added comment section 3 on Modular Extension to DTD.
 
      27. Edited text of many Use: comments
 
 
    2001-03-05 Revision 3-08
 
       1. Updated version number to 3-08.
 
       2. Removed outer parentheses from element content models
          for: level, level1, level2, level3, level4,
               level5, level6.
 
       3. Changed occurrence indicator for element types that
          include (#PCDATA | ...)+ to "(#PCDATA | ...)*" as
          required by XML applications for:
              imgcaption, blockquote, lic

       4. Eliminated parameter entities whose need has vanished
          from HTML since version 3.2, changed content models
          to (#PCDATA):
              % scriptcm "#PCDATA"
              % stylesheetcontent "#PCDATA"
 
       5. Relaxed content model for li to (%flow; | lic)*
 
       6. Element head: added parentheses around content model.
          For consistency with xhtml, required title needn't
          be first.
 
       7. Eliminated unreferenced parameter entity:
 
              % calign ("top" | "bottom" | "left" | "right")
 
       8. Moved ATTLISTs to immediately follow the element
          declarations to which they apply: done for table
          elements and inline elements.
 
       9. Moved some comments about attributes into the Use
          comment so they propagate to the html version.
 
      10. % scope entity moved to be with other table entities
          and changed to Scope per HTML 4.0 strict dtd.
 
      11. head content model aligned with XHTML to allow just
          arbitrary order for title, and optional base, without
          requiring strict order.
 
      12. Copied from xhtml1.1 some comments, identified
          by xhtml: prefix therein.
 
      13. li attributes: amplified explanation.
 
      14. Changed the imported parameter entity names to
          contain the same capitalization or CamelCase
          names as in the HTML 4.0 strict dtd. [they had
          all been lowercase.]
          capitalization as in HTML 4.0 strict dtd, and in XHTML:
              Character, Charset, Charsets, ContentType,
              ContentTypes, Datetime, LanguageCode, LinkTypes,
              MediaDesc, URI, Script, StyleSheet, Text
          Others are also changed, noted in the sections where
          they are used:
              Coords, Length, MultiLength, Pixels, Scope, Shape,
              TFrame, TRules.
          Note: in XHTML parameter entity names differing only
          in case occur:
              % Block contains %block;, and
              % Inline contains %inline;.
          The use herein of %block; and %inline; is from HTML 4.0.
          It does not match that XHTML convention.
 
      15. Eliminated parameter entity MultiLengths, unreferenced
          in HTML 4.0 strict DTD.
 
      16. Changed blockquote to eliminate %inline, comparable
          to xhtml.
 
   2001-04-20  Revision 3-09
 
       1. % block added line to permit designated line of
          content, some of which may have linenum.
 
       2. % block added imggroup to permit group of img, possibly
          with imgcaptions and prodnotes.
 
       3, % block added horizontal rule hr to show separation,
 
       4. % inlines added %externalinline; for extensibility to
          modules declared in document internal subset in sentence.
 
       5. % inlinenopagenum added %externalinline; for
          extensibility to modules declared in document
          internal subset in tables.
 
       6. list repaired ambiguous content model so by convention
          at most one hd.
 
       7. list enum attribute Note that the enum attribute values
          are case-sensitive, but some tools fail to make that
          distinction. Revised values for enum to avoid the
          case sensitivity: changed "A" to "U" for uppercase
          letter and "I" to "X" for uppercase roman number.
 
       8. % head.misc added object for consistency with xhtml.
 
       9. Expansion and clarification of the externalID for
          referencing the dtbook3 DTD, and adding reference to
          the Oasis-Open "socat" entity management system.
 
     -->

============================================================================
 
<!-- hb Revision 3-10 changes to DTBook3-09 as of 2001-09-04, requested by
    Michael M. Moodie:

    1. Change naming scheme to include version number, which will always
        have three digits.  First digit changes for a major new version.
        Second digit changes for moderate changes.  Third digit changes
        for minor fixes to DTD.  Initial name will be: dtbook100.dtd.

    2. Change document element name from dtbook3 to dtbook.

    3. Add FIXED "version" attribute to dtbook element. Value for first
        official version of DTD will be: 1.0.0

    4. Remove restriction that doctitle must come first in <frontmatter>.
        It can appear, only once, anywhere a block element can appear.
        (Production tools will have to enforce that it can appear only
        once in a dtbook document.)

    5. Add new element docauthor to unambiguously mark the book's author.
        It can appear, multiple times, anywhere a block element can appear.
        Add to <author> a statement "Compare with docauthor."

    6. Drop element <base>.

    7. Fix problem noted with character entities:
        lt, amp, and gt are required to be pre-defined in any xml processor.
        Use Unicode entities throughout, rather than using ISO 8859-1
        explicitly.

    8. Make <frontmatter> optional within <book>.

    9. Drop the <a> element as a block and retain as inline element.

   10. Modify ATTLIST for <a> to drop the following attributes:
        charset, shape, coords, onfocus, onblur.  Provide descriptions for
        the remaining attributes, as needed.

   11. Change content model of <address> to allow <line> within it.

   12. Drop from description of <sidebar> the last sentence (which
        mentions href).

   13. Drop <var>.

   14. Change first sentence of description of <pagenum> to read:
        Contains a page number from the print document, inserted at the
        point within the file immediately preceding the first item of
        content on a new page.

   15. ATTLIST pagenum
       %attrs;
       page   (front | normal | special)  #IMPLIED'
       Need a requirement for any application to default this to 'normal'.

   16. Drop ELEMENT <object>.

   17. Drop ELEMENT <param>.

   18. Drop ELEMENT <script>.

   19. Drop ELEMENT <noscript>.

   20. Drop from intro material the reference to a list of compatible modules.

   21. Add new element <annotation>.

   22. Add new element <annoref> that can be used to reference an
        annotation.  Allows <annoref>s  to be turned off separately
        from <noteref>s.

   23. Correct section of DTD that discusses modularization, adding
        SYSTEM identifier to examples. Also discuss effect of using
        parameter entities from dtbook100.dtd in included modules.
        System shown won't work if they are used. So either expand them
        to their individual values or develop new names for them and
        define them in the module.

   24. Change ELEMENT <citation> to <cite>.

   25. Add new attribute smilref to parameter entities %attrs; and %attrsrqd;.

   26. Drop <imgcaption> and just use <caption> within <table> or <imggroup>.
        Add an attribute imgref (of type IDREFS, IMPLIED) to the ATTLIST
        for <caption>, and modify the definition for <caption>.


    hb Version 3-10 Changes 2001-09-07 by Harvey Bingham

    hb     1. fixed typos.
    hb     2. added reference to XHTML 1.0: The Extensible HyperText
              Markup Language [XHTML11] and its [XHTML11STRICT] strict.dtd
              as source for element name comparisons:
                  http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd
    hb     3. updated SMIL 2.0 W3C status to recommendation.
    hb     4. updated XML reference to Second Edition.
                  http://www.w3.org/TR/2000/REC-xml-20000106.
    hb     5. Updated reference for html elements to xhtml1 strict.dtd
    hb     6. clarified element Use: descriptive comments for several
              element types.
    hb     7. changed URLs for drama.dtd and poem.dtd to phony ones.
    hb     8. Changed representations to hexadecimal for XML-required
              character entities.
    hb     9. changed % attrs showin default from "blp" to #IMPLIED.
    hb    10. Replaced citation by cite, compatible with XHTML1.0.
    hb    11. Proposed: omit %events; from %attrs;
    hb    12. Added reference comments for parameter entities from xhtml.
    -->

<!--hb Version 3-11 Revisions 2001-09-21

    Changes 2001-09-21 to dtbook3-10 requested by Michael M. Moodie:

    0. Fixed some typos and clarification requests, skipped from record below.

    1. Purpose - para 4.  Changed to read SMIL 2.0, instead of 2.0.1.

    2. Purpose - para 4. Replaced with the following:

       The dtbook DTD includes many, but not all, of the elements found in
       HTML. HTML authoring tools may include many of the additional tags
       that are left out of dtbook. Endtag markup, sometimes optional in
       HTML, is required in dtbook, as any XML application requires endtags.
       The benefit of including endtags is that the tagged document has
       dependable structure.

    3. Document Tagging Content - para 1. Added "optional" before
       "character set."

    4. Dropped sentence: "That name, "dtbook100" matches the root element
       name of the document." The root element is "dtbook". The version
       attribute on it tells you what version you have, as does the DTD name.

    5. Added System literal to first sentence of para following example, so
       it now reads: The second string of the PUBLIC ExternalID
       ("dtbook100.dtd") is called SystemLiteral. It is a URI indicating
       where on the local system the dtd file can be found.

    8. Fixed Public URI (added "100" to dtbook.dtd) in this section:

       For example:

        <!DOCTYPE dtbook PUBLIC
        "http://www.loc.gov/nls/z/dtbook100.dtd"
        "dtbook100.dtd"

       hb: adjusted above from original request.

    9. Dropped from change 5 (re docauthor) the statements:  Definition
       should include statement "Compare with <author>." Add to <author>
       a statement "Compare with docauthor."

   15. Changed first sentence of last para of ENTITY declaration for showin
       to read: It is possible to include equivalent content from any
       major structure below book to provide the different content
       suitable for different media.

   18. Changed definition of annotation to read: Use: annotation is a
       comment on or explanation of a portion of a document. Differs from
       note in that an annotation is usually set in the margin or on a
       facing page, often with no reference to it inserted in the text.
       Any local reference to an annotation with id="xxx" is by
       <annoref idref="#xxx">.

   19. Changed definition of docauthor to read: Use: docauthor marks each
       author or editor of this work. Compare with <author>, used to mark
       the author of another work, within <blockquote> or <cite>, for example.

   20. Changed definition of doctitle to read: Use: doctitle marks the title
       of the book within <frontmatter>. By convention it should appear only
       once, usually first.

   21. Changed definition of author to read : Use: author identifies the
       writer of a work other than this one. Compare with <docauthor> which
       identifies the author of this work.

   22. Changed definition of img to read: Use: img marks a visual image.
       The "src" attribute specifies the location of the image file. The
       "alt" and "longdesc" attributes may be used to supply short and long
       descriptions, respectively, although prodnote will generally contain
       the latter. Longdesc may contain a pointer to the prodnote. The
       referencing is typically of the form <caption imgref="#yyy">The
       Caption</caption> for the printed caption of the <img id="yyy">.

   23. Added "or descriptions" to comment about <img> as follows:
       "Image <img> comes from HTML. An <img> may be grouped
       using <imggroup>, with <caption>, and special usage instructions
       or descriptions with <prodnote>. The <imggroup> element may contain
       one or more <img> and any associated <caption> and <prodnote>.
       Multiple <img> may share a single caption, or multiple <caption>
       may apply if several captions refer to a single <img>. Multiple
       <prodnote> may apply if different versions are needed for different
       media."

   24. Changed root element from dtbook100 to dtbook. Document
       Structure section revised accordingly, to read as follows:

       Use: dtbook is the root element in the Digital Talking Book DTD.
       Contains metadata in <head> and the document itself in <book>.

           <!ELEMENT dtbook (%dtbook.content;)>

           <!ATTLIST dtbook
               version CDATA #FIXED '1.0.0'
               %i18n; >
       hb: changed version to CDATA.

   25. Changed segment describing DOCTYPE to reference dtbook instead of
       dtbook100, as follows:

       "This is followed by the document type declaration, the DOCTYPE:

        <!DOCTYPE dtbook PUBLIC
            "http://www.loc.gov/nls/niso/dtbook100.dtd"
            "dtbook100.dtd">

       hb: changed that form to the current location.

   26. Changed another segment to reference dtbook instead of dtbook100
       in DOCTYPE, as follows:

       An alternative for ExternalID is to begin with SYSTEM instead of PUBLIC,
       followed by SystemLiteral URI indicating where on the local system the
       dtd file can be found.

        <!DOCTYPE dtbook SYSTEM "dtbook.dtd">

       hb: revised that to dtbook.dtd

   27. Changed 3rd para from end of section 3 to read as follows (used full
       name of DTD instead of DTBook100 or DTBook) Make sure I'm right on
       this one.:

       "The fully marked-up document follows, including tags declared from the
       included external modules. Since declarations in the internal subset
       take precedence over like-named ones from the external entity
       containing the base DTD (that is, dtbook100.dtd), the module containing
       the drama and poem tags is included along with the tags in the base
       DTD that are not duplicated in the drama module. So if a <p> tag is
       defined in the drama module, its definition overrides that of the <p>
       tag in dtbook.

   28. Changed fifth paragraph in section 4 to read as follows
       (corrected name of html file):

       The last beta version was dtbook3-09.dtd.

         http://www.loc.gov/nls/niso/dtbk3-09.dtd
         http://www.loc.gov/nls/niso/dtbk3-09doc.htm

   31. Corrected description of tbody to read as follows (returned to original
       form in version 3-09):  "Use: tbody marks a group of rows in the main
       body of a table. If the table is divided into several sections, each
       consisting of a number of rows, each section would be separately tagged
       with <tbody>.

   32. Corrected description of th to read as follows (inverted order of
       clauses "possibly within a row" and "breaking most anywhere"):

   33. Corrected description of td to read as follows (inverted order of
       clauses "possibly within a row" and "breaking most anywhere"):

   35. Eliminate the requirement for <a name="xxx"> as target for
       <a href="xxx">.

   36. Revise Use of annotation.

   37. Revise Use of annoref.

   38. Revise smilref.

    Changes 2001-09-21 to dtbook3-11 draft by Harvey Bingham

    hb     1. Expanded on the DOCTYPE declaration, distinguishing root
              dtbook from particular version URLS starting with dtbook100.dtd.

    hb     2. Augmented the discussion on internal subset, suggesting but
              not detailing that xml modules could be used as well.

    hb     3. Clarified comment about required endtags on empty elements.

    hb     4. added missing quotes on defined character entities.

    hb     5. Restored DOCTYPE formal public identifier, presuming that
              the OASIS Entity Management method or equivalent will be used to
              determine the FPI to URI mapping.

    hb     6. Expanded Use on annotation.

    hb     7. Augmented Use: on table to include tables with just rows.

    hb     8. Augmented thead and tfoot Use: to describe their effect on
              multi-page tables.

    hb     9. Marked many other element names in USE: with <...>.

    hb    10. Augmented Use: on style to include xml:space.

    hb    11. img eliminated usemap and ismap attributes since we have
              no map element, and those attributes are used in conjunction
              with map.

    hb    12. Added explanations of attribute values. Some may not be indicated
              by HB: comment.

    hb    13. Added many Use: to identify attribute uses.
              Some of these are not individually indicated by HB: comments.

    hb    14. Added comments after many parameter entities. [not completely
              checked, nor individually indicated with HB: comment.]

    hb    15. Reformatted attlists consistently.

    hb    16. Eliminated the subsection on Client-side image maps,
              as not needed.
    -->

<!--hb Revisions for Version 3-12 2001-09-26

    Changes 2001-09-26 to dtbook3-11 requested by Michael M. Moodie:

    Prefix numbers below are substantive, ignoring numbers for others,
    including removal of prior change requests, or typos.
    
    5. Why are code and samp handled differently regarding xml:space? 
    
       hb: <samp> should not have that constraint, necessarily to preserve
       whitespace. A sample may be a form letter. <style> and <code> 
       xml:space (preserve) #FIXED 'preserve'.
    
    10. USE: level3 "subsections within subsections" should be
        "subsections within sections".
        
        hb: extended that idea to all <levelN>
      
    11. ELEMENT a Use: Rewrite/simplify.

    12. Do we really want to suggest idref on noteref might point to the
        block containing it?  Not sure we know enough to say that. 
        Drop everything after &lt;note id="yyy"&gt;:
    
    14. Use: table contains cells of tabular data arranged in rows and columns.
            A <table> may have a <caption>. It may have descriptions of
            the columns in <col>s or groupings of them in <colgroup>.
            A simple <table> may be made up of just rows <tr>.
            A long table crossing several pages of the print book should
            have separate <pagenum> values for each of the pages containing
            that <table> indicated on the page where it starts.
            Note the logical order of optional <thead>, optional <tfoot>,
            then one or more of either <tbody> or just rows <tr>. This order
            accommodates simple or large, complex tables. <thead> and <tfoot>
            information usually helps identify content of the <tbody> rows,
            For a multiple-page <table> the <thead> and <tfoot> are repeated
            on each page.
    
            The summary attribute value provides a textual summary.
            The attributes: width, border, frame, rules, cellspacing, and
            cellpadding provide visual presentation guidance.
    
    20. Section 2, "Document Tagging Content" attacks a very complex subject,
        unnecessarily.
        hb: simplified

    hb Version 3-12 Changes 2001-09-26 by Harvey Bingham

    hb  1. Added attribute descriptions throughout for the attributes
           that are not explained by their parameter entities:
               level, div, prodnote, a, samp, acronym, bdo, pagenum,
               noteref, img, levelhd, blockquote, list, table, caption,
               colgroup, col, tr, th, td, head, title, link, meta, style

    hb  2. Expanded some Use descriptions.

    hb  3. Repaired ampersand &amp; on character entity definitions for it
           and less than, and in comments.

    hb  4. %attrs; and %attrsrqd; added usage comment.

    hb  5. Added usage comments after all parameter entity declarations.

    hb  6. author augmented use to contrast with docauthor.

    hb  7. annotation augmented use to contrast with note.

    hb  8. a eliminated "name" attribute, explained href target is id.
           amplified attribute descriptions.

    hb  9. code added xml:namespace

    hb 10. img eliminated usemap and ismap attributes. 
    
    hb 11. p augmented use, can be container for list and dl.

    hb 12. doctitle use added contrast with title in head.

    hb 13. blockquote augmented use to include cite attribute.

    hb 14. lic use added condition of correspondence of li.

    hb 15. table extended model to match xhtml, allowing simple 
           table of just rows. Use explains multiple page tables.

    hb 16. thead use on multiple page table, not repeated.

    hb 17. tfoot use on multiple page table, not repeated

    hb 18. tbody use whe multiple shares thead and tfoot.

    hb 19. col augmented use to account for span.
    
    -->

<!-- Detailed change comments by HB from Versions 3-10 thru 3-12.-->

<!--HB: 2001-09-07 Character entities changed representations to Unicode
 hexadecimal for XML-required character entities.

<!--HB: 2001-09-26 repaired lt and amp escaping of "&amp;" only on first,
 providing that "&amp;" entity reference prefix needed for the second.

<!--HB: 2001-09-07 Parameter Entity Names: added comments from xhtml strict.dtd
 eliminated % Script, added references in brackets for those comments.

<!--HB: 2001-09-07 % dtbookblock added annotation. Note that the internal
 subset that may give value to %externalblock; can reference in its
 content no parameter entities in this DTD.

<!--HB: 2001-09-07 %inlineinblock; changed citation to <cite>, removed code
 and var.

<!--HB: 2001-09-07 % block removed noscript.

<!--HB: 2001-09-21 showin added parameter entity for use in %attrs;
 and %attrsrqd;.

<!--HB: 2001-09-07 % events eliminated from %attrs; as unused.

<!--HB: 2001-09-07 attrs eliminated %events; Added smilref as allowed by
 production process to augment document with references to the ID values
 therein.

<!--HB: 2001-09-26 attrs appended usage comment.

<!--HB: 2001-09-07 attrsrqd eliminated %events; Added smilref so
 the production process can augment document with references to the ID
 values therein.

<!--HB: 2001-09-26 attrsrqd appended usage comment.

<!--HB: 2001-09-07 dtbook changed root elementname from dtbook3 and
 added version attribute with value "1.0.0" #FIXED.

<!--HB: 2001-09-26 div Use added attribute usage.

<!--HB: 2001-09-07 book made <frontmatter> optional, implication: may have
 no <booktitle>.

<!--HB: 2001-09-07 book attlist: eliminate onload and onunload
 as they use %Script;.

<!--HB: 2001-09-07 frontmatter added <docauthor>, moved <doctitle> into
 or group. Eliminated script. Several <docauthor> may occur.

<!--HB: 2001-09-07 bodymatter eliminated script from <bodymatter>.

<!--HB: 2001-09-07 rearmatter eliminated script from <rearmatter>.

<!--HB: 2001-09-26 level Use added attribute usage.

<!--HB: 2001-09-07 % phrase: changed citation to cite, removed var.

<!--HB: 2001-09-07 % special: removed object and script.

<!--HB: 2001-09-07 % speciala: removed object and script.

<!--HB: 2001-09-07 address added <line> that can be used to enclose the
 distinct lines of an address. The class attribute can give meaning
 to each such line.

<!--HB: 2001-09-26 div Use added attribute usage.

<!--HB: 2001-09-26 author augmented Use: to contrast with <docauthor>.

<!--HB: 2001-09-26 prodnote Use added attribute usage.

<!--HB: 2001-09-07 sidebar adjusted use description.

<!--HB: 2001-09-07 note Use: removed mention of annotation which becomes a
 distinct element type.

<!--HB: 2001-09-07 annotation element type added so can be separately
 skippable from <note>.

<!--HB: 2001-09-26 annotation augmented Use to contrast with <note>.

<!--HB: 2001-09-07 % Shape Eliminated entity as no longer needed.

<!--HB: 2001-09-07 % Coords Eliminated entity as no longer needed.

<!--HB: 2001-09-07 a eliminated attributes: charset, shape, coords,
 onfocus, onblur. Added descriptions of remaining attributes.
 Altered tabindex from NMTOKENS to %Number; and name from CDATA
 to NMTOKEN per [XHTML11STRICT] strict.dtd. Added explanations of the
 attributes from that dtd.

<!--HB: 2001-09-26 a eliminated name attribute, allow reference
 using href to target an id value. Amplified attribute discussion.

<!--HB: 2001-09-26 a Use added attribute usage.

<!--HB: 2001-09-07 var removed element type.

<!--HB: 2001-09-26 code added attribute xml:space to permit preserving
 whitespace.

<!--HB: 2001-09-26 samp Use added xml:space and attribute usage.

<!--HB: 2001-09-07 var removed element type.

<!--HB: 2001-09-07 cite replaced citation by <cite>, compatible with XHTML1.0
 added comment on possible inclusion within <a ...>.

<!--HB: 2001-09-26 acronym Use added attribute usage.

<!--HB: 2001-09-07 span augmented Use to allow placement of id value on
 otherwise #PCDATA following an inline.

<!--HB: 2001-09-26 bdo Use added attribute usage.

<!--HB: 2001-09-07 pagenum add to Use:
 For multipage continuous content, such as large <img> or <table>,
 put the sequence of <pagenum> on the page where that content starts.
 Changed default value for page from #IMPLIED to normal.
 As <pagenum> are targets for referencing, changed from %attrs; to
 %attrsrqd; so a unique id is required.

<!--HB: 2001-09-26 pagenum Use added attribute usage.

<!--HB: 2001-09-26 noteref Use added attribute usage.

<!--HB: 2001-09-07 annoref added element type.

<!--HB: 2001-09-26 annoref Use added attribute usage.

<!--HB: 2001-09-26 q Use added attribute usage.

<!--HB: 2001-09-26 Image parameter entities: added following comments.

<!--HB: 2001-09-26 img eliminated usemap and ismap attributes since we have
 no map element, and those attributes are used in conjunction with map.

<!--HB: 2001-09-26 img Use added attribute usage.

<!--HB: 2001-09-07 object deleted element type.

<!--HB: 2001-09-07 param deleted element type.

<!--HB: 2001-09-25 p augmented definition

<!--HB: 2001-09-07 doctitle revised Use to no longer require it to be first.

<!--HB: 2001-09-26 doctitle added contrast with <title> in <head>.

<!--HB: 2001-09-07 docauthor added to mark each book author (or editor)

<!--HB: 2001-09-26 levelhd Use added attribute usage.

<!--HB: 2001-09-26 blockquote to include the cite attribute.

<!--HB: 2001-09-26 list Use added attribute usage.

<!--HB: 2001-09-26 lic added condition of correspondence in <li>.

<!--HB: 2001-09-07 forms eliminated section as without content.

<!--HB: 2001-09-26 table extended model to match xhtml strict.dtd by
 allowing a <table> of just rows <tr>. Eliminated datapagesize
 attribute. Augmented Use description to include multiple pages.

<!--HB: 2001-09-26 table Use added attribute usage.

<!--HB: 2001-09-07 caption added attribute by which one or more <img>s
 to which it applies can be referenced, and expanded Use.

<!--HB: 2001-09-26 caption Use added attribute usage.

<!--HB: 2001-09-26 thead augmented Use to discuss repeated content use
 for multiple-page <table>.

<!--HB: 2001-09-26 tfoot augmented Use: to discuss repeated content use
 for multiple-page <table>.

<!--HB: 2001-09-26 tbody augmented Use to describe common <thead>
 and <tfoot> for multiple <tbody>.

<!--HB: 2001-09-07 colgroup Use made consonant with xhtml strict.dtd

<!--HB: 2001-09-26 colgroup Use augmented to account for span,
 added attribute usage.

<!--HB: 2001-09-26 col augmented Use to account for span.

<!--HB: 2001-09-26 col Use added attribute usage.

<!--HB: 2001-09-26 tr Use added attribute usage.

<!--HB: 2001-09-26 th Use added attribute usage.

<!--HB: 2001-09-26 td Use added attribute usage.

<!--HB: 2001-09-07 % head.misc eliminated script and object.

<!--HB: 2001-09-07 head eliminated base.

<!--HB: 2001-09-26 head Use added attribute usage.

<!--HB: 2001-09-26 link Use added attribute usage.

<!--HB: 2001-09-07 base eliminated element type.

<!--HB: 2001-09-26 meta Use added attribute usage.

<!--HB: 2001-09-07 style added to Use: may include CDATA sections,
 attribute xml:space for consistency with xhtml strict.dtd.

<!--HB: 2001-09-26 style Use added attribute usage.

<!--HB: 2001-09-07 script element eliminated.

<!--HB: 2001-09-07 noscript element eliminated.