edited by Witold Marciszewski
Martinus Nijhoff Publishers, 1981
Buku Referensi
Owen, David
Routledge , 1994
Buku Teks
Tran, Van Doan, author
The council for research in values and philosophy, 2001
Buku Teks
Pagels, Heinz R.
Simon and Schuster , 1988
Buku Teks
Alexander, Christopher, author
Harvard University Press, 1964
Buku Teks