Thomas, Henry
Blakiston, 1946
Buku Teks
Christensen, Kit R.
McGraw-Hill, 2002
Buku Teks
edited by F.S.C. Northrop
Yale University Press, 1949
Buku Teks
Iannone, A. Pablo
Routledge, 2001
Buku Referensi
Reader in Philosophy, University of The Panjab, 1965
Buku Teks