Covey, S. R. (2004). The 8th habit: From effectiveness to greatness. Free Press.
Lua i Stíl Chicago (17ú heag.)Covey, Stephen R. The 8th Habit: From Effectiveness to Greatness. New York: Free Press, 2004.
Lua MLA (8ú heag.)Covey, Stephen R. The 8th Habit: From Effectiveness to Greatness. Free Press, 2004.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.