Lipset, Seymour Martin, author
Basic Books, 1963
Buku Teks
Angle, Paul M
Fawcett Publications,Inc, 1960
Buku Teks
Olsen, Edward A, author
Praeger Security International, 2005
Buku Teks
Tinbergen, Jan, 1903-, author
Yale University Press, 1964
Buku Teks
Wilder
Gramedia, 1956
Buku Teks