Rossiter, Tony, author
Financial World, 2011
Buku Teks
Buchan, John
Longmans, Green and Co. , 1950
Buku Teks
Russell, Lou, author
American Society for Training & Development, 2007
eBooks
Appleman, Jack E., author
2009
eBooks
Vukotich, George, author
American Society for Training & Development, 2011
eBooks