Whitmore, T.C.
Clarendon Press, 1990
Buku Teks SO
Jacobs, Marius
Springer-Verlag, 1981
Buku Teks SO
edited by F.B. Golley
Elsiver, 1983
Buku Referensi
edited by Helmut Lieth, M.J.A. Werger and David W. Goodall
Elsevier, 1992
Buku Teks SO
edited by Mark Collins ; foreword by David Attenborough
Oxford University Press, 1990
Buku Teks SO