Canterucci, Jim, author
American Management Association;, 2005
eBooks
Derlega, Valerian J.
Scott Foresman , 1981
Buku Teks
Covey, Sean, author
[publisher not identified], [date of publication no identified]
Buku Teks
Covey, Sean, author
A Fireside Book, 2004
Buku Teks
DuBrin, Andrew J., author
Reston Publishing Company, 1983
Buku Teks