Vicki Smith, Patrizia Collard, Paula Nicolson, Rowan Bayne
Mc Graw-Hill, 2012
Buku Teks
Singer, Erwin
Random House, 1965
Buku Teks
Sage Publications, 2002
Buku Teks
Brent D. Slife, Richard N. Williams, and Sally H. Barlow
Sage, 2001
Buku Teks
Brammer, Lawrence M., author
Prentice-Hall, 1982
Buku Teks