Hickok, Eugene W.
The Free Press, 1993
Buku Teks
Singh, Robert
Polity Press, 2002
Buku Teks
Frank, Jerome
Princeton University press, 1973
Buku Teks
Jenkins, Jeffrey A. , author
Jones and Bartlett Publishers LLC , 2011
Buku Teks
Jacob, Herbert, 1933-, author
Yale University Press, 1996
Buku Teks