Gamble, Teri Kwal, author
American Society for Training & Development, 2007
eBooks
Sugars, Bradley J., author
McGraw-HIll , 2006
Buku Teks
Johnson, Spencer, author
Harper Collins, 2004
Buku Teks
Ardyan Yudha, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2013
UI - Skripsi (Membership)
Lapp, Charles L.
McGraw-Hill, 1957
Buku Teks