Frederick, J. G. (1929). Selling by telephone. Business Bourse Publishers.
Čikaški stil citiranja (17. izdanje)Frederick, J. George. Selling by Telephone. New York: Business Bourse Publishers, 1929.
MLA način citiranja (8. izdanje)Frederick, J. George. Selling by Telephone. Business Bourse Publishers, 1929.
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