Hall, Peter
Routledge, 2011
Buku Teks
Freeman, T.W.
Hutchinson University Library, 1974
Buku Teks
edited by Andrew Blowers and Bob Evans
Routledge, 1997
Buku Teks
Davidson, Joan
Pergamon Press, 1977
Buku Teks
Cullingworth, J.B.
Allen & Unwin, 1973
Buku Teks