Number of headings:
2 Subject Headings for medium level.
6 Subject Headings for high level.
1 Subject Heading for more than 20% of the work.
Generally do not assign subject headings for literary works unless they are on a specific topic.
Order of headings:
For original cataloguing, use the guidelines on Order of Subject Headings in the LC Subject Cataloguing Manual (H80).
For copy cataloguing, do not change the original order of the headings.
For copy cataloguing, it is not necessary to update existing $x to $v.
If a record only contains juvenile LCSH, MeSH or other local headings, add LCSH heading/s as appropriate.
690 / 691 Local subject access fields
For maps and music, institution specific subject headings (691 and 690 respectively) are used for Australian items.This copied from "National Library of