Trident Press, [Date of publication not identified]
Buku Referensi
edited by Philip Sutton and Hazel M. Mitchell
CABI, 2010
Buku Teks
Greed, Clara H., author
[publisher not identified], [date of publication no identified]
Buku Teks
Brown, A.J., author
Melbourne University Press, 1951
Buku Teks
Gillie, F.B., author
The Hague, 1971
Buku Teks