United States. Postmaster General. (1928). Redemption of canceled stamped envelopes and postal cards. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Postmaster General. Redemption of Canceled Stamped Envelopes and Postal Cards. Washington: U.S. GPO, 1928.
MLA (9th ed.) CitationUnited States. Postmaster General. Redemption of Canceled Stamped Envelopes and Postal Cards. U.S. GPO, 1928.
Warning: These citations may not always be 100% accurate.