Coertze, R.D.
ABRA , 1987
Buku Teks
Carsrud, Alan L.
Springer, 2011
eBooks
Hutley, F.C. (Francis Charles)
Law Book, Co., 1975
Buku Teks
Gardner, John
Macmillan, 1982
Buku Teks
Hastings, Sandra
American Society for Training and Development Press, 2005
eBooks