Weston, Michael, author
Routledge , 2001
Buku Teks
Lamarque, Peter, author
Blackwell Publishing, 2009
Buku Teks
edited by A. Phillips Griffiths
Cambridge University Press, 1984
Buku Teks
Garry L. Hagberg and Walter Jost, editors
Wiley Balckwell, 2010
Buku Teks
New, Christopher, author
Routledge, 1999
Buku Teks