Dyfyniad APA

Covey Stephen R. (2004). 7 Habits of highly effective people. Pocket Books.

Dyfyniad Arddull Chicago

Covey Stephen R. 7 Habits of Highly Effective People. London: Pocket Books, 2004.

Dyfyniad MLA

Covey Stephen R. 7 Habits of Highly Effective People. Pocket Books, 2004.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.