APA (7th ed.) Citation

United States. Postmaster General. (1932). Arbor Day commemorative postage stamp. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Arbor Day Commemorative Postage Stamp. Washington: U.S. GPO, 1932.

MLA (9th ed.) Citation

United States. Postmaster General. Arbor Day Commemorative Postage Stamp. U.S. GPO, 1932.

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