Usher, M.B.
Chapman and Hall , 1973
Buku Teks
Eagles, Paul F.J.
Longman, 1984
Buku Teks
Hambler, Clive, 1960-, author
Cambridge University Press , 2013
Buku Teks
Dasmann, Raymond F. (Raymond Fredric), author
John Wiley & Sons, 1975
Buku Teks
Spellerberg, Ian F., author
Cambridge University Press, 1992
Buku Teks