Raven, Peter H.
Worth Publisher, 1986
Buku Referensi
Laetsch, Watson M.
Little, Brown, 1979
Buku Teks
Corner, E.J.H.
The World Publishing Company, 1964
Buku Teks
Attenborough, David
BBC Worldwide Limited, 2005
Multimedia
Attenborough, David
BBC Worldwide Limited, 2005
Multimedia