Dingus, Lowell
Carlton, 2012
Buku Referensi
editor, G.R. Castro and M. Cardona
Springer-Verlag Berlin Heidelberg, 1987
Buku Teks
Tahija, Jean
Australia Viking, 1998
Buku Teks
Craffi, Stephen
Image Publishing, 2002
Buku Teks
Smith, Jim
American Society for Training & Development, 2008
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