Daniels, Kathy, author
Chartered Institute of Personnel and Development, 2012
Buku Teks
Grollman, Arthur
Lea & Febiger, 1962
Buku Teks
Rhodes, A. J.
The Williams & Willkins, 1958
Buku Teks
[edited by] Robert S. Beardsley, Carole L. Kimberlin, William N. Tindall
Wolters Kluwer/Lippincott Williams & Wilkins, 2012
Buku Teks
Dickson, Donald T.
New York Free Press 1998,
Buku Teks