Ries , A. &. (1990). Bottom-up marketing. Penguin.
Lua i Stíl Chicago (17ú heag.)Ries , Al &Trout. Bottom-up Marketing. New York: Penguin, 1990.
Lua MLA (9ú heag.)Ries , Al &Trout. Bottom-up Marketing. Penguin, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.