Hawkins, Peter
Open University Press, 2005
Buku Teks
Sue Wheeler, David King
Sage Publications, 2001
Buku Teks
edited by Michael Parker
Routledge , 1999
Buku Teks
Judson, Karen, 1941-
McGra-Hill Connect Learn Succeed, 20103
Buku Teks
Kerridge, Ian
Social Science Press, 1998
Buku Teks