Wilber, Charles K.
McGraw-Hill , 1992
Buku Teks
Bagchi, Amiya Kumar, author
Cambridge University Press , 1984
Buku Teks
Kiching, Covin
Methuen, 1982
Buku Teks
Staniland, Martin, author
RajaGrafindo Persada, 2003
Buku Teks
Loomis, Charles P., author
D Van Nostrand , 1965
Buku Teks