APA (7th ed.) Citation

Library of Congress & Subjet Cataloging Division. (1999). Library of Congress Subject Headings (21st. ed.). The National Bibliographic Service.

Chicago Style (17th ed.) Citation

Library of Congress and Subjet Cataloging Division. Library of Congress Subject Headings. 21st. ed. Washington: The National Bibliographic Service, 1999.

MLA (9th ed.) Citation

Library of Congress and Subjet Cataloging Division. Library of Congress Subject Headings. 21st. ed. The National Bibliographic Service, 1999.