McBride, John, author
BBC Books , 1996
Buku Teks
Estep, Tora, author
American Society for Training & Development, 2006
eBooks
Rossiter, Tony, author
Financial World, 2011
Buku Teks
Willmore, Job, author
American Society for Training & Development, 2009
eBooks
Russell, Lou, author
American Society for Training & Development, 2007
eBooks