Covey Stephen R. (2004). Seven habits Of Highly Effective People. Simon Schuster.
Citazione stile Chigago Style (17a edizione)Covey Stephen R. Seven Habits Of Highly Effective People. London: Simon Schuster, 2004.
Citatione MLA (9a ed.)Covey Stephen R. Seven Habits Of Highly Effective People. Simon Schuster, 2004.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.