Robbins, Paul, author
Wiley-Blackwell, 2010
Buku Teks
Giddens, Anthony, author
Harcourt, Brace Javanovich, 1982
Buku Teks
Brownlee, Ian, author
Longman, 1998
Buku Teks
Ward, Ian, author
Routledge. Cavendish. Taylor & Francis Group, 2004
Buku Teks
Sole, Mary Lou, author
Elsevier , 2005
Buku Teks