Toth, A. G., author
Clarendon Press, 1990
Buku Referensi
Cuthbert, Mike
Cavendish Publishing Limited, 1993
Buku Teks
Shaw, Josephine, author
Macmillan, 1993
Buku Teks
Groves, Peter J., author
Cavendish, 1995
Buku Teks
edited by Robert M. Maclean
[Publisher not identified], [Date of publication not identified]
Buku Teks