APA (7th ed.) Citation

United States. Post Office Department. (1939). U.S. Official Postal Guide, 5th Series; June 1939. [s.n.].

Chicago Style (17th ed.) Citation

United States. Post Office Department. U.S. Official Postal Guide, 5th Series; June 1939. [Washington]: [s.n.], 1939.

MLA (9th ed.) Citation

United States. Post Office Department. U.S. Official Postal Guide, 5th Series; June 1939. [s.n.], 1939.