Roper, D. C. (1917). The United States post office: Its past record, present condition, and potential relation to the new world era. Funk & Wagnalls company.
Chicagoスタイル(17版)引用形式Roper, Daniel C. The United States Post Office: Its Past Record, Present Condition, and Potential Relation to the New World Era. New York and London: Funk & Wagnalls company, 1917.
MLA(8版)引用形式Roper, Daniel C. The United States Post Office: Its Past Record, Present Condition, and Potential Relation to the New World Era. Funk & Wagnalls company, 1917.
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