Godin, S. (2002). Purple Cow. Penguin Books.
Lua i Stíl Chicago (17ú heag.)Godin, Seth. Purple Cow. London: Penguin Books, 2002.
Lua MLA (9ú heag.)Godin, Seth. Purple Cow. Penguin Books, 2002.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.