APA (7th ed.) Citation

United States. Postmaster General. (1918). To postmaster. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. To Postmaster. Washington: U.S. GPO, 1918.

MLA (9th ed.) Citation

United States. Postmaster General. To Postmaster. U.S. GPO, 1918.

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