Beckwith Harry. (1997). Selling the invisible: A field guide to modern marketing. Warner Books / Time Warner Company.
Chicago-referens (17:e uppl.)Beckwith Harry. Selling the Invisible: A Field Guide to Modern Marketing. NewYork ,USA: Warner Books / Time Warner Company, 1997.
MLA-referens (9:e uppl.)Beckwith Harry. Selling the Invisible: A Field Guide to Modern Marketing. Warner Books / Time Warner Company, 1997.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.