Pounds, Norman J. G.
World geography
Silver Burdett, 1980
 Buku Teks
World geography
edited by Otis W. Freeman and John W. Morris
McGraw-Hill, 1958
 Buku Teks
World geography
edited by Otis W. Freeman and John W. Morris
McGraw-Hill, 1958
 Buku Teks
Funk & wagnalls new encyclopedia Vol. 27, Vermont to World War II
Funk & Wagnalls, 2000,
 Buku Referensi
Carlson, Lucile
Geography and world politics
Prentice-Hall, 1960
 Buku Teks