APA (7th ed.) Citation

United States. Postmaster General. (1931). Some efficient methods of reducing volume of undeliverable mail. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Some Efficient Methods of Reducing Volume of Undeliverable Mail. Washington: U.S. GPO, 1931.

MLA (9th ed.) Citation

United States. Postmaster General. Some Efficient Methods of Reducing Volume of Undeliverable Mail. U.S. GPO, 1931.

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