APA (7th ed.) Citation

United States. Postmaster General. (1926). Information regarding 3rd-class post offices. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. Information Regarding 3rd-class Post Offices. Washington: U.S. GPO, 1926.

MLA (9th ed.) Citation

United States. Postmaster General. Information Regarding 3rd-class Post Offices. U.S. GPO, 1926.

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