APA (7th ed.) Citation

United States. Postmaster General. (1919). Washington city post office, Christmas mail. [publisher not identified].

Chicago Style (17th ed.) Citation

United States. Postmaster General. Washington City Post Office, Christmas Mail. [Place of publication not identified]: [publisher not identified], 1919.

MLA (9th ed.) Citation

United States. Postmaster General. Washington City Post Office, Christmas Mail. [publisher not identified], 1919.

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