United States. Postmaster General. (1920). Instructions and rulings with reference to transportation of mails by railroads under space system of authorization and payment (effective Mar. 1, 1920). U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Postmaster General. Instructions and Rulings with Reference to Transportation of Mails by Railroads Under Space System of Authorization and Payment (effective Mar. 1, 1920). Washington: U.S. GPO, 1920.
MLA (9th ed.) CitationUnited States. Postmaster General. Instructions and Rulings with Reference to Transportation of Mails by Railroads Under Space System of Authorization and Payment (effective Mar. 1, 1920). U.S. GPO, 1920.
Warning: These citations may not always be 100% accurate.