Campion, H.
Oxford University Press, 1939
Buku Teks
Ng-Loy, Wee Loon, author
Sweet & Maxwell Asia, 2009
Buku Teks
Supperstone, Michael, author
Longman, 1994
Buku Teks
Cooke, Darryl J., author
Sweet & Maxwell, 2011
Buku Teks
Goldstein, Paul, author
Little, Brown, 1989
Buku Teks