Dill, William R.
Prentice-Hall, 1962
Buku Teks
Bittel, Lester Robert, author
Addison-Wesley Publishing Company, Inc., 1987
Buku Teks
Shaver, Warren, author
[American Society for Training & Development Press, ], 2000
eBooks
Cooper, Alfred M., author
McGraw-Hill, 1958
Buku Teks
Cooper, Alfred M., author
McGraw-Hill, 1963
Buku Teks