Hass, K. (1969). Creative salesmanship understanding essentials. George Press.
Citazione stile Chigago Style (17a edizione)Hass, K. Creative Salesmanship Understanding Essentials. London: George Press, 1969.
Citatione MLA (9a ed.)Hass, K. Creative Salesmanship Understanding Essentials. George Press, 1969.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.