Russel, F. A., & Beach, F. H. Test book of salesmanship (6th ed.). McGraw Hill bok company.
Chicago Edition CitationRussel, Fredrick A., i Frank H. Beach. Test Book of Salesmanship. 6th ed. New York: McGraw Hill bok company.
Cita MLARussel, Fredrick A., i Frank H. Beach. Test Book of Salesmanship. 6th ed. McGraw Hill bok company.
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