edited by A.T. Dalfovo
The Council for Research in Values and Philosophy , 2002
Buku Teks
Murray, Rachel, author
Cambridge University Press, 2004
Buku Teks
Nino, Carlos Santiago
Oxford University , 1993
Buku Teks
Printer Publishers , 1988
Buku Teks
Welch, Claude E., author
University of Pennsylvania, 1995
Buku Teks