Hass, K. (1969). Creative salesmanship understanding essentials. George Press.
Čikaški stil citiranja (17. izdanje)Hass, K. Creative Salesmanship Understanding Essentials. London: George Press, 1969.
MLA način citiranja (9. izdanje)Hass, K. Creative Salesmanship Understanding Essentials. George Press, 1969.
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