APA (7th ed.) Citation

United States. Postmaster General. (1929). Use of envelopes having loose flap and body held together with spot of gum. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Use of Envelopes Having Loose Flap and Body Held Together with Spot of Gum. Washington: U.S. GPO, 1929.

MLA (9th ed.) Citation

United States. Postmaster General. Use of Envelopes Having Loose Flap and Body Held Together with Spot of Gum. U.S. GPO, 1929.

Warning: These citations may not always be 100% accurate.