Canfield, B. R. (1958). Salesmanship; Practice and Problems (3rd ed.). McGraw-Hill.
Dyfyniad Arddull ChicagoCanfield, Bertrand R. Salesmanship; Practice and Problems. 3rd ed. New York: McGraw-Hill, 1958.
Dyfyniad MLACanfield, Bertrand R. Salesmanship; Practice and Problems. 3rd ed. McGraw-Hill, 1958.
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