A Library of Congress Classification number is added to a heading if the caption for the number is identical or nearly identical in scope, meaning, and language to the subject heading, or if the topic is explicitly mentioned in an "Including" note under the caption for the number. Multiple class numbers may be added to a heading when the subject is treated from more than one perspective. For the heading of a subject covered by a span of class numbers, the full span of pertinent class numbers is included.

12.0 References

See also:

Principles of Heading Construction