David Boucher, Paul Kelly, editor
Oxford Univesity Press, 2009
Buku Teks
Kymlicka, Will, author
Clarendon Press, 1990
Buku Teks
Ebenstein, William, author
Thomson Learning, 2000
Buku Teks
Pojman, Louis P., author
McGraw-Hill , 2003
Buku Teks
THe Free Press, 1961
Buku Teks