APA (7th ed.) Citation

United States. Postmaster General. (1932). Three-cent stamp books. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Three-cent Stamp Books. Washington: U.S. GPO, 1932.

MLA (9th ed.) Citation

United States. Postmaster General. Three-cent Stamp Books. U.S. GPO, 1932.

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