APA (7th ed.) Citation

Library of Congress. Catalog Division. (1920). Classification, outline scheme of classes. GPO.

Chicago Style (17th ed.) Citation

Library of Congress. Catalog Division. Classification, Outline Scheme of Classes. [Washington]: GPO, 1920.

MLA (9th ed.) Citation

Library of Congress. Catalog Division. Classification, Outline Scheme of Classes. GPO, 1920.

Warning: These citations may not always be 100% accurate.