Easterbrook, Don J.
Macmillan Publishing Company, 1993
Buku Teks
Gregory, Kenneth J.
Sage , 2010
Buku Teks
Bloom, Arthur L.
Prentice Hall of India, 1979
Buku Teks
Easterbrook, Don J.
McGraw-Hill, 1969
Buku Teks
Djamang Ludiro
Jurusan Geografi FMIPA Universitas Indonesia, 1993
Buku Teks SO