Covey, S. R. (2004). 8th Habit from effectiveness to greatness (Audio Book). Simon & Schuster Inc.
Lua i Stíl Chicago (17ú heag.)Covey, Stephen R. 8th Habit from Effectiveness to Greatness (Audio Book). New York: Simon & Schuster Inc, 2004.
Lua MLA (9ú heag.)Covey, Stephen R. 8th Habit from Effectiveness to Greatness (Audio Book). Simon & Schuster Inc, 2004.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.