Ries , A. &. (1990). Bottom-up marketing. Penguin.
Cita Chicago Style (17a ed.)Ries , Al &Trout. Bottom-up Marketing. New York: Penguin, 1990.
Cita MLA (9a ed.)Ries , Al &Trout. Bottom-up Marketing. Penguin, 1990.
Precaución: Estas citas no son 100% exactas.