United States. Post Office Department. (1930). Cost ascertainment report showing cost of carrying and handling several classes of mail matter and of performing special services for fiscal year 1931. GPO.
Chicago Style (17th ed.) CitationUnited States. Post Office Department. Cost Ascertainment Report Showing Cost of Carrying and Handling Several Classes of Mail Matter and of Performing Special Services for Fiscal Year 1931. [Washington]: GPO, 1930.
MLA (9th ed.) CitationUnited States. Post Office Department. Cost Ascertainment Report Showing Cost of Carrying and Handling Several Classes of Mail Matter and of Performing Special Services for Fiscal Year 1931. GPO, 1930.
Warning: These citations may not always be 100% accurate.