Beckwith Harry. (1997). Selling the invisible: A field guide to modern marketing. Warner Books / Time Warner Company.
Citazione stile Chigago Style (17a edizione)Beckwith Harry. Selling the Invisible: A Field Guide to Modern Marketing. NewYork ,USA: Warner Books / Time Warner Company, 1997.
Citatione MLA (9a ed.)Beckwith Harry. Selling the Invisible: A Field Guide to Modern Marketing. Warner Books / Time Warner Company, 1997.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.