United States. Post Office Department. (1942). United States Official Postal Guide; Monthly Supplement to Parts I and II; April 1942. [publisher not identified].
Chicago Style (17th ed.) CitationUnited States. Post Office Department. United States Official Postal Guide; Monthly Supplement to Parts I and II; April 1942. [Washington]: [publisher not identified], 1942.
MLA (9th ed.) CitationUnited States. Post Office Department. United States Official Postal Guide; Monthly Supplement to Parts I and II; April 1942. [publisher not identified], 1942.
Warning: These citations may not always be 100% accurate.