Nichol, John, author
David & Charies, 1990
Buku Referensi
Whitmore, T.C., author
Clarendon Press, 1990
Buku Teks
Jacobs, Marius, author
Springer-Verlag, 1981
Buku Teks
edited by Helmut Lieth, M.J.A. Werger and David W. Goodall
Elsevier, 1992
Buku Teks
edited by F.B. Golley
Elsiver, 1983
Buku Referensi