Friga, Paul N, author
McGraw-Hill, 2009
Buku Teks
Woo, Julia T.
Harper & Row , 1986
Buku Teks
Woods, Donald R.
Waterdown, 1994
Buku Teks
Vrooman, Rona J., author
[American Society for Training & Development Press, American Society for Training & Development Press], 2000
eBooks
Prince, George M.
Harper & Row , 1970
Buku Teks