Elliott, David
Routledge , 1997
Buku Teks
edited by Bob Everett, Godfrey Boyle, Stephen Peake and Janet Ramage
Oxford University Press, 2012
Buku Teks
Coley, David
John Wiley & Sons, 2008
Buku Teks
Outhwaite, William
Blackwell, 2006
Buku Teks
Birkhauser GmbH, 2008
Buku Referensi