|First Indicator||Second Indicator|
# - Undefined
0 - Library of Congress Subject Headings
1 - LC subject headings for children's literature
2 - Medical Subject Headings
3 - National Agricultural Library subject authority file
4 - Source not specified
5 - Canadian Subject Headings
6 - Répertoire de vedettes-matière
7 - Source specified in subfield $2
Form subdivision term that is equivalent to the 155 genre/form or 185 form subdivision field of the same record. It links headings within a system or from different thesauri or authority files.
Most of the content designators defined for field 785 are the same as those defined for field 185 (Heading-Form Subdivision), field 485 (See From Tracing-Form Subdivision), and field 585 (See Also From Tracing-Form Subdivision). Description, guidelines, and input conventions for shared content designators are given in the X85 Form Subdivisions-General Information section.
Guidelines for applying the second indicator, subfield $w (Control subfield), subfield $2 (Source of heading or term), subfield $i (Relationship information), and subfield $4 (Relationship code) in field 785 are given in the 7XX Heading Linking Entries-General Information section.
Established heading genre/form term is also used as a form subdivision; no separate subdivision record:
[established heading record]
[code indicating LCSH]