Coertze, R.D.
ABRA , 1987
Buku Teks
Carsrud, Alan L.
Springer, 2011
eBooks
Hutley, F.C. (Francis Charles)
Law Book, Co., 1975
Buku Teks
Atwood, Christee Gabour
American Society for Training & Development, 2007
eBooks
Hastings, Sandra
American Society for Training and Development Press, 2005
eBooks