APA (7th ed.) Citation

(1937). Postal bulletin, May 5, 1937. [s.n.].

Chicago Style (17th ed.) Citation

Postal Bulletin, May 5, 1937. [Washington]: [s.n.], 1937.

MLA (9th ed.) Citation

Postal Bulletin, May 5, 1937. [s.n.], 1937.

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