Covey, S. R. (2004). The 7 Habits of Highly Effective People. Pocket Books.
Cita Chicago (17th ed.)Covey, Stephen R. The 7 Habits of Highly Effective People. Pocket Books, 2004.
Cita MLA (9th ed.)Covey, Stephen R. The 7 Habits of Highly Effective People. Pocket Books, 2004.
Atenció: Aquestes cites poden no estar 100% correctes.