Covey, S. R. The 7 habits of highly effective people: Restoring the character ethic (Revised edition.).
Lua i Stíl Chicago (17ú heag.)Covey, Stephen R. The 7 Habits of Highly Effective People: Restoring the Character Ethic. Revised edition.
Lua MLA (8ú heag.)Covey, Stephen R. The 7 Habits of Highly Effective People: Restoring the Character Ethic. Revised edition.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.