Laurel Saville, Steve Gordhan, Jodhua Berger, Sarch Dougher, editor
Page one publishing pte ltd, 2011
Buku Referensi
Thompson, Willard M.
McGraw-Hill , 1968
Buku Teks
Mcevoy, Sean
Routledge, 2006
Buku Teks
Russell, Jeffrey
American Society for Training & Development, 2006
eBooks
Haneberg, Lisa
American Society for Training & Development, 2006
eBooks