COVEY STEPHEN R. (1990). 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. FIRESIDE BOOK.
Chicago-Zitierstil (17. Ausg.)COVEY STEPHEN R. 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. LONDON: FIRESIDE BOOK, 1990.
MLA-Zitierstil (9. Ausg.)COVEY STEPHEN R. 7 HABITS OF HIGHLY EFFECTIVE PEOPLE: POWERFUL LESSONS IN PERSONAL CHANGE. FIRESIDE BOOK, 1990.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.