Constantino, Renato, author
Karrel, 1989
Buku Teks
Gregor, A. James
Ethics and Public Policy Center, 1984
Buku Teks
edited by Raul P. De Guzman, Mila A. Reforma
Oxford University Press, 1988
Buku Teks
Merriam, Charles E. (Charles Edward), author
New York University Press, 1936
Buku Teks
Solomos, John, author
Routledge, 1995
Buku Teks