APA (7th ed.) Citation

U. S. Library of Congress. Reference Department. (1949). A Guide to special book collections in the Library of Congress.

Chicago Style (17th ed.) Citation

U. S. Library of Congress. Reference Department. A Guide to Special Book Collections in the Library of Congress. Washington, 1949.

MLA (9th ed.) Citation

U. S. Library of Congress. Reference Department. A Guide to Special Book Collections in the Library of Congress. 1949.