Covey, S. R. (1989). The seven habits of highly effective people: Restoring the character ethic. Simon and Schuster.
Citazione stile Chigago Style (17a edizione)Covey, Stephen R. The Seven Habits of Highly Effective People: Restoring the Character Ethic. New York: Simon and Schuster, 1989.
Citatione MLA (8a ed.)Covey, Stephen R. The Seven Habits of Highly Effective People: Restoring the Character Ethic. Simon and Schuster, 1989.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.