Levesque, Joseph D.
Prentice-Hall, 1996
Buku Referensi
Liff, Stewart
American Management Association;, 2010
eBooks
Griffeth, Rodger
Sage Publications , 2001
Buku Teks
Bradley, Elihu F.
ASM International, 1989
Buku Referensi
Lauby, Sharlyn J.
[American Society for Training and Development Press;, ], 2005
eBooks