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
Carlson, Lucile
Geography and world politics
Prentice-Hall, 1960
 Buku Teks
Heintzelman, Oliver H.
World regional geography
Prentice-Hall, 1960
 Buku Teks
Heintzelman, Oliver H.
World regional geography
Prentice-Hall, 1965
 Buku Teks