Covey, Stephen R.
Simon & Schuster, 2013
Buku Teks
Covey, Stephen R.
Simon & Schuster, 2013
Buku Teks
Covey, Sean
A Fireside Book, 2004
Buku Teks
Covey, Sean
[publisher not identified], [date of publication no identified]
Buku Teks
Covey, Stephen R.
A Fireside Book, 1989
Buku Teks