Hass, K. (1969). Creative salesmanship understanding essentials. George Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रHass, K. Creative Salesmanship Understanding Essentials. London: George Press, 1969.
एमएलए (9वां संस्करण) प्रशस्ति पत्रHass, K. Creative Salesmanship Understanding Essentials. George Press, 1969.
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