Palmer, Robert Roswell, 1909-2002
Princeton University Press, 1964
Buku Teks
Routledge , 1996
Buku Teks
Harvie, Christopher
Routledge , 1994
Buku Teks
Linz, Juan J.
Johns Hopkins University Press, 1978
Buku Teks
Palmer, Monte
Thomson Wadsworth, 2007
Buku Teks