Planty, Earl G.
Ronald Press Company, 1948
Buku Teks
Albright, Mary
Prentice-Hall, 1997
Buku Teks
Boller, Sharon, author
American Society for Training & Development, 2005
eBooks
Agus M. Hardjana, author
Kanisius, 2001
Buku Teks
Tamblyn, Doni, author
McGraw-HIll, 2000
Buku Teks