Covey, S. (1992). The seven habits of highly effective people. Simon & Schuster.
Lua i Stíl Chicago (17ú heag.)Covey, Stephen. The Seven Habits of Highly Effective People. London: Simon & Schuster, 1992.
Lua MLA (9ú heag.)Covey, Stephen. The Seven Habits of Highly Effective People. Simon & Schuster, 1992.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.