APA (7th ed.) Citation

United States. Post Office Department. (1922). Service rating system. GPO.

Chicago Style (17th ed.) Citation

United States. Post Office Department. Service Rating System. [Washington]: GPO, 1922.

MLA (9th ed.) Citation

United States. Post Office Department. Service Rating System. GPO, 1922.

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