Arnaud, A. A.
Woodhead-Faulkner, 1985
Buku Teks
Todd, Paul, author
London : Balckstone, 1994,
Buku Referensi
Haley, Michael, author
Sweet and Maxwell, 2007
Buku Teks
Mennell, Robert L., author
West Publishing, 1994
Buku Teks
Evans, Michael
Butterworth, 1993
Buku Teks