Denhardt, Robert B., author
Harcourt College, 1999
Buku Teks
by Dwight Waldo ... [et.al.]
Duke University Press, 1970
Buku Teks
Gaus, John M., author
University of Alabama Press, 1055
Buku Teks
Shafritz, Jay M., author
Wadsworth/Thompson Learning, 2004
Buku Teks
Fesler, James W. (James William), 1911-2005, author
Prentice-Hall, 1980
Buku Teks