Griffin, Roger, author
Routledge, 1994
Buku Teks
Maritain, Jacques
Philosophical Library, 1951
Buku Teks
Wallis, W. Allen, author
The Free Press, 1966
Buku Teks
Yates, Steve, author
Facts On File, 1992
Buku Referensi
Meyer, Eric, author
Prentice Hall Press, 2001
Buku Teks