Artikel Jurnal
Edited by Catherine Suyak Alloway
The Scarecrow Press, Inc., 1990
Buku Teks
Gurton, Annie, author
Prentice-Hall, 1998
Buku Teks
Bhote, Keki R., author
American Management Association, 2004
eBooks
Kouzes, James M., author
Jossey-bass, 2012
Buku Teks