Black, Lloyd D.
D. Van Nostrand Company, Inc., 1968
Buku Teks
McNeill, Desmond
Croom Helm, 1981
Buku Teks
Penguin Books , 1970
Buku Teks
Wolf, Charles
Princeton University Press , 1960
Buku Teks
White, John, author
The Overseas Development Institute, 1967
Buku Teks