APA (7th ed.) Citation

United States. Postmaster General. (1931). Undeliverable catalogues bearing pledge to pay return postage must be promptly returned. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Undeliverable Catalogues Bearing Pledge to Pay Return Postage Must Be Promptly Returned. Washington: U.S. GPO, 1931.

MLA (9th ed.) Citation

United States. Postmaster General. Undeliverable Catalogues Bearing Pledge to Pay Return Postage Must Be Promptly Returned. U.S. GPO, 1931.

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