Hand, Amy
American Society for Training & Development, 2010
eBooks
Elliot, Rose
Chapmans Publisher Ltd., 1994
Buku Referensi
Minrath, William R.
D. Van Nostrand, 1956
Buku Teks
Doucett, Elisabeth
[American Management Association, ], 2008
eBooks
Lewis, Herschell Gordon
Prentice-Hall, 1986
Buku Teks