Jones, David J., author
Australia, Second Back Row Press
Buku Referensi
Jones, David J.
Second Back Row Press, 1981
Buku Teks
Paxton, John, author
J.M. Dent & Sons, 1992
Buku Referensi
Merriam-Webster, 1985
Buku Referensi
Brown, Wendy E., author
McGraw-Hill, 1993
Buku Referensi