Orum, Anthony M.
Rowman & Littlefield Publishers, 1999
Buku Teks SO
Gelb, Joyce
Holt, Rinehart and Winston, 1971
Buku Teks
Findlay, Mark
Cambridge University Press, 1999
Buku Teks
edited by Thomas R. Dye, Brett W. Hawkins
Charles E. Merrill, 1967
Buku Teks
Inglehart, Ronald, 1934-
Cambridge University Press, 2018
Buku Teks