Claringbull, Norman, author
Learning Matters, 2011
Buku Teks
Bager-Charleson, Sofie, author
Learning Matters, 2011
Buku Teks
Kottler, Jeffrey A., author
John Wiley & Sons, 2009
Buku Teks
Whitaker, Carl A.
The Blakiston Company, 1953
Buku Teks
Corsini, Raymond J.
John Wiley & Sons, 1981
Buku Teks