Waard, Hendrik de, author
Addison-Wesley, 1966
Buku Teks
Sapienza, Alice M., author
Wiley, 2004
Buku Teks
Harvard Business School
Harvard business review press, 2011
Buku Teks
Estep, Tora, author
American Society for Training & Development, 2006
eBooks
McBride, John, author
BBC Books , 1996
Buku Teks