Goldman, William
A Dell Book, 1960
Buku Teks
Whitmore, T.C.
Clarendon Press, 1990
Buku Teks
edited by Mark Collins ; foreword by David Attenborough
Oxford University Press, 1990
Buku Teks
Restu Sulistyorini
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2013
UI - Skripsi Membership
Veevers-Carter, W.
Oxford University Press , 1984
Buku Teks