United States. Postmaster General. (1929). Requests for changes in envelope orders. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Postmaster General. Requests for Changes in Envelope Orders. Washington: U.S. GPO, 1929.
MLA (9th ed.) CitationUnited States. Postmaster General. Requests for Changes in Envelope Orders. U.S. GPO, 1929.
Warning: These citations may not always be 100% accurate.