The Encyclopaedia of mammals
edited by David Macdonald
Facts on File, 1993
 Buku Referensi
Encyclopaedia Britannica : volume 2
Encyclopaedia Britannica Inc., 1967
 Buku Referensi
Encyclopaedia Britannica : volume 2
Encyclopaedia Britannica Inc., 1968
 Buku Referensi
The Australian encyclopaedia : volume 2
Grolier Society of Australia, 1983
 Buku Referensi
Encyclopaedia universalis : volume 2
Encyclopaedia Universalis France S.A. , 1989
 Buku Referensi