Gallie, W.B.
Middlesex, Penguin Books, 1952
Buku Teks
Ayer, Alfred Jules, 1910-1989
Freeman, Coope, 1968
Buku Teks
James, William
Meridian Books , 1959
Buku Teks
by Simon Critchle ... [et al.] ; edited by Chantal Mouffe
Routledge, 1996
Buku Teks
Peirce, Neal R.
W. W. Norton, 1983
Buku Teks