Shafritz, Jay M., author
Wadsworth/Thompson Learning, 2004
Buku Teks
Fesler, James W. (James William), 1911-2005, author
Prentice-Hall, 1980
Buku Teks
Berkley, George E., author
McGraw-Hill, 2009
Buku Teks
edited by Maurice E. O'Donnell
Houghton Mifflin, 1966
Buku Teks
by Phillip J. Cooper [and others]
Harcourt Brace, 1998
Buku Teks