COVEY STEPHEN R. (1990). 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. FIRESIDE BOOK.
Lua i Stíl Chicago (17ú heag.)COVEY STEPHEN R. 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. LONDON: FIRESIDE BOOK, 1990.
Lua MLA (9ú heag.)COVEY STEPHEN R. 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. FIRESIDE BOOK, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.