Stephen R Covey. (2004). 7 habits of highly effectie people. Pocket books.
Dyfyniad Arddull ChicagoStephen R Covey. 7 Habits of Highly Effectie People. London: Pocket books, 2004.
Dyfyniad MLAStephen R Covey. 7 Habits of Highly Effectie People. Pocket books, 2004.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.