Bruhn, John G.
Charles C. Thomas Publisher, 1993
Buku Teks
Sampson, Edward E., author
John Wiley & Sons, 1981
Buku Teks
edit by Brenda Freshman, Louis Rubino, Yolanda (Linda) Reid Chassiakos
Jones and Bartlett, 2010
Buku Teks
McConnell, Charles R., author
Jones & Bartlett Learning, 2013
Buku Teks
McConnell, Charles R., author
Jones & Bartlett Learning, 2013
Buku Referensi