Handlin, Oscar, author
Atheneum, 1966
Buku Teks
Laski, Harold J., author
George Allen and Unwin, 1948
Buku Teks
Laski, Harold J., author
Penguin Books, 1937
Buku Teks
Mill, John Stuart, author
David Campbell Publisher, 1992
Buku Referensi
Dahrendorf, Ralf, author
Stanford University Press, 1975
Buku Teks