Barron, Jerome A., author
West, 2009
Buku Teks
Smith, Glenn C., author
John Wiley & Sons, 2012
Buku Teks
John Ferejohn, Jack N. Rakove, Jonathan Riley
Cambridge University Press, 2001
Buku Teks
Fisher, Louis, author
McGraw-Hill, 1988
Buku Teks
Pritchett, C. Herman, author
McGraw-Hill, 1981
Buku Teks