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
Reader in Philosophy, University of The Panjab, 1965
Buku Teks
edited by John K. Ryan
The Catholic University of America Press, 1963
Buku Teks