Snead, G. Lynne, author
A Fireside Book, 1997
Buku Teks
Kong, Pyong-ho, 1960-
21-segi Puksu, 2002
Buku Teks
Maxey, Cindy, author
American Society for Training & Development, 2007
eBooks
Easwaran, Eknath, author
Gramedia Pustaka Utama, 2003
Buku Teks
Sinaga, Harez Porma, author
Universitas Indonesia, 1989
UI - Skripsi (Membership)