Rees, Nigel, author
Cassell Publishers, 1995
Buku Referensi
Kamm, Antony, author
Harper Collins Pub., 1993
Buku Referensi
Jones, David J., author
Australia, Second Back Row Press
Buku Referensi
Jones, David J.
Second Back Row Press, 1981
Buku Teks
Adam, J.H., author
York Press, 1989
Buku Referensi