APA (7th ed.) Citation

United States. Postmaster General. (1930). New varieties of stamped envelopes to be issued. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. New Varieties of Stamped Envelopes to Be Issued. Washington: U.S. GPO, 1930.

MLA (9th ed.) Citation

United States. Postmaster General. New Varieties of Stamped Envelopes to Be Issued. U.S. GPO, 1930.

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