Healey, Bede, author
Georgian House, 1972
Buku Teks
Goodpaster, Gary, author
University of California, 1993
Buku Teks
Schmeckebier, Laurence F.
The Brookings Institution, 1934
Buku Teks
Kosambi
Vikas Publishing House, 1975
Buku Teks
Western Press Agency, 1962
Buku Teks