Gould, Nick, author
Routledge, 2016
Buku Teks
edited by Jerrold R. Brandell
Free Press, 1997
Buku Teks
Brieland, Donald, author
McGraw-Hill, 1975
Buku Teks
Aspinwall-Roberts, Elaine, author
McGraw-Hill, 2012
Buku Teks
Laycock, A. L.
Routledge , 1970
Buku Teks