Fletcher, Shirley, author
Gramedia, 2005
Buku Teks
edited by M.D. Jitendra
Anmol Publications,
Buku Referensi
Cohen, William A., author
American Management Association, 2008
eBooks
Routledge, 2000
Buku Teks
Toenniges, Lisa, author
[American Society for Training and Development Press;, ], 2005
eBooks