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DATE: December 9, 2015
NAME: Extending the Use of Subfield $0 to Encompass Linking Fields in the MARC 21 Bibliographic Format
SOURCE: British Library
SUMMARY: This paper discusses the definition of subfield $0 (Authority record control number or standard number) in linking entry fields 760, 762, 765, 767, 770, 772, 773, 774, 775, 776, 777, 780, 785, 786, 787 in the MARC 21 Bibliographic Format.
KEYWORDS: Authority record control number or standard number (BD); Subfield $0, in Linking Entry Fields (76X-78X) (BD); Subfield $i, in 7XX fields (BD); Relationship information (BD); URIs (BD)
RELATED: 2010-DP02 ; 2009-06/1; 2010-06 ; 2011-08 ; 2015-07
12/09/15 – Made available to the MARC community for discussion.
01/10/16 – Results of MARC Advisory Committee discussion: The Committee agreed that this paper should return as a discussion paper or proposal depending on whether the follow up paper contains any outstanding questions which require analysis. The scope of $4 (Relationship code) should be redefined to support the recording of URIs for relationships between resources. In raising a follow up paper, the British Library will collaborate with the PCC Task Group on URIs in MARC.
The MARC Bibliographic format makes provision for relating different resources using added entry fields 700, 710, 711 and 730. It also supports the recording of these relationships using linking fields 76X-78X. Subfield $i (Relationship information) designates the relationship between the resource described in the 700/710/711/730 or 76X-78X and the resource described in the 1XX/245 fields of the record. Subfield $i can be used to record controlled terms for the relationships between works, expressions, manifestations and items as defined in RDA. At present it is possible to record URIs (Uniform Resource Identifiers) for these controlled terms using subfield $0 (Authority record control number or standard number) in fields 700, 710, 711 and 730. However, subfield $0 is not defined in fields 76X-78X. The British Library suggests that subfield $0 could be defined in fields 76X-78X as a means of supporting linked data applications in a way that could already be catered for in fields 700, 710, 711 and 730.
Following the implementation of RDA, subfield $i has been used in MARC fields 700/710/711/730 and 76X-78X to record relationship designators between resources as defined by Appendix J (Relationship Designators: Relationships Between Works, Expressions, Manifestations and Items). This was facilitated by MARBI’s approval of MARC Proposal 2009-06/1 which amended the subfield’s label and definition to specify that its purpose was for recording relationship information rather than general display text:
$i - Relationship information (700/710/711/730)
Designation of a relationship between the resource described in the 7XX field and the resource described in the 1XX/245 of the record. This may be an uncontrolled textual phrase or a controlled textual value from a list of relationships between bibliographic resources.
$i - Relationship information (76X-78X)
Designation of a relationship between the resource described in the 76X-78X field and the resource described in the 1XX/245 of the record. This may be in the form of uncontrolled text or a controlled text value. The second indicator contains value 8 (No display constant generated) except in fields 780 and 785 when data in this subfield is intended to be displayed. The data in subfield $i can be displayed preceding the other data contained in the field.
For each relationship defined in RDA Appendix J, a URI is available from the RDA Registry. It is already possible to record these in fields 700, 710, 711 and 730 using subfield $0. This follows MARBI’s approval of MARC Proposal 2010-06 which amended the subfield label and definition of $0 to encompass the recording of standard numbers as well as authority control numbers:
$0 - Authority record control number or standard number
Subfield $0 contains the system control number of the related authority record, or a standard identifier such as an International Standard Name Identifier (ISNI). The control number or identifier is preceded by the appropriate MARC Organization code (for a related authority record) or the Standard Identifier source code (for a standard identifier scheme), enclosed in parentheses. See MARC Code List for Organizations for a listing of organization codes and Standard Identifier Source Codes for code systems for standard identifiers. Subfield $0 is repeatable for different control numbers or identifiers.
The following example sets out the encoding of an ISNI standard identifier in relation to a name authority heading:
100 1# $a Trollope, Anthony, $d 1815-1882. $0 (isni) 0000000121358464
Besides ISNI, the MARC list for Standard Identifier Source Codes accommodates other types of standard number. The code “uri” is used to identify the presence of a uniform resource identifier. The approval of MARC Proposals 2011-08 and 2015-07 enabled the use of subfield $0 for encoding URIs (Uniform Resource Identifiers) associated with controlled vocabularies. URIs for terms relating to carrier characteristics are available from the RDA Registry; URIs for terms relating to content, media and carrier type are available from the RDA Registry and id.loc.gov.
The following example demonstrates coding of the URI for a vocabulary term available from the RDA Registry:
344 ## $a analog $0 (uri) http://rdaregistry.info/termList/typeRec/1001
The following example demonstrates coding of the URI for a vocabulary term available from id.loc.gov:
338 ## $a audio disc $0 (uri) http://id.loc.gov/vocabulary/carriers/sd $2 rdacarrier
In a scenario where subfield $0 is used to code a URI from the RDA Registry in fields 700, 710, 711 and 730 it would be desirable to code this following subfield $i. This is because the URI does not apply to name or title data recorded in the name or title portion, but only to relationship information recorded at the beginning of the field. At present the MARC formats do not mandate this approach but nor do they proscribe it. MARC Discussion Paper 2010-DP02 discusses the options available to encode URIs for controlled values. It notes that:
“extensive rules would need to be written to specify subfield sequencing. The automated systems libraries use would need to be able to retain and understand the importance of subfield sequencing.”
MARC Proposal 2010-06 makes the assumption that the ISNI represents the entity represented by the whole heading, not entities which constitute components of the heading. Under these circumstances, they would not occur in fields containing subfield $t (Title of awork). Since recording the URI for a work relationship term would be predicated on the presence of $t in fields 700, 710, 711 and 730, this paper assumes than the same field would not contain both a URI for that term and an ISNI, VIAF or other identifier for the name. However, a situation could arise in which the same field contains a URI for the entity relationship term and a URI for the entity itself, such as a VIAF Work or Expression ID. If subfield $0 were defined in fields 76X-78X then the same principle of sequencing and the same scope of $0 usage would be expected to apply.
The following example models the encoding of an RDA Registry URI associated with the work level relationship “paraphrase of (work)”:
700 1# $i paraphrase of (work) $0 (uri) http://rdaregistry.info/Elements/u/#P60296 $a Tippett, Michael, $d 1905-1998.$t Mask of time.
The following example models the recording of an RDA Registry URI associated with the manifestation level relationship “also issued as (manifestation)”:
776 08 $i also issued as (manifestation) $0 (uri) http://rdaregistry.info/Elements/u/#P60195 $a Aylett, David. $t With voice divine. $d [England] : [D. Aylett], 2008
The following example models the recording of an RDA Registry URI associated with the manifestation level relationship “reproduction of (manifestation)”:
787 08 $i reproduction of (manifestation) $0 (uri) http://rdaregistry.info/Elements/u/#P60297 $a Verdi, Giuseppe, 1813-1901. $t Otello. $d Milano: Ricordi, c1913
Including linking information to data in MARC will facilitate the transition to fuller linking in BIBFRAME.
5.1. Is the principle of using subfield sequence to reflect the relationship between $i (Relationship information) and $0 (Authority record control number or standard number ) acceptable?
5.2. If the sequencing of subfield $0 is not acceptable to reflect such a relationship, then should the MARC formats make this explicit?
5.3. If subfield sequencing is acceptable to reflect the relationship, then should subfield $0 be defined in fields 76X-78X in order to support the recording of URIs?
5.4. If the definition of subfield $0 is not acceptable in fields 76X-78X, then are there any alternative subfields which may be defined or re-scoped in order to support the recording of URIs, for example $4 (Relationship code)?
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