DeLamater, John D.
Colorado Westview Press, 2014
Buku Teks
Victoria University of Wellington, 2007
Buku Teks
Taylor, Shelley E.
Prentice-Hall, 1997
Buku Teks
Baron, Robert A.
Allyn and Bacon , 1997
Buku Teks
Myers, David G.
McGraw-Hill, 2005
Buku Teks