United States. Post Office Department. (1930). Undeliverable matter bearing pledge to pay return postage must be promptly returned. GPO.
Chicago Style (17th ed.) CitationUnited States. Post Office Department. Undeliverable Matter Bearing Pledge to Pay Return Postage Must Be Promptly Returned. [Washington]: GPO, 1930.
MLA (9th ed.) CitationUnited States. Post Office Department. Undeliverable Matter Bearing Pledge to Pay Return Postage Must Be Promptly Returned. GPO, 1930.
Warning: These citations may not always be 100% accurate.