Huntington, Samuel P., author
Simon & Schuster, 2005
Buku Teks
Griffiths, Peter, author
Edward Arnold, 1987
Buku Teks
Artikel Jurnal
Aby, Stephen H., 1949-, author
Greenwood Press, 1990
Buku Teks
Berelson, Bernard, author
The Population Council, 1975
Buku Teks