APA (7th ed.) Citation

U. S. Library of Congress. Subject Cataloging Division & Library of Congress. Classification Division. (1957). Classification. Class P, subclasses P-PM supplement: Index to languages and dialects (Second edition.). [U. S. Government Printing Office].

Chicago Style (17th ed.) Citation

U. S. Library of Congress. Subject Cataloging Division and Library of Congress. Classification Division. Classification. Class P, Subclasses P-PM Supplement: Index to Languages and Dialects. Second edition. Washington: [U. S. Government Printing Office], 1957.

MLA (9th ed.) Citation

U. S. Library of Congress. Subject Cataloging Division and Library of Congress. Classification Division. Classification. Class P, Subclasses P-PM Supplement: Index to Languages and Dialects. Second edition. [U. S. Government Printing Office], 1957.