APA (7th ed.) Citation

United States. Postmaster General. (1929). Business reply cards and letters in business reply envelopes may be prepared for return via air mail. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Business Reply Cards and Letters in Business Reply Envelopes May Be Prepared for Return via Air Mail. Washington: U.S. GPO, 1929.

MLA (9th ed.) Citation

United States. Postmaster General. Business Reply Cards and Letters in Business Reply Envelopes May Be Prepared for Return via Air Mail. U.S. GPO, 1929.