Thakur, Ramesh Chandra
Westview Press, Inc, 1987
Buku Teks
edited by William J. Durch
Macmillan, 1994
Buku Teks
White, N.D., author
Manchester University Press, 1993
Buku Teks
McCoubrey, Hilaire, author
Brookfield Dartmouth , 1995
Buku Teks
Bowett, D.W. (Derek William), author
Frederck A. Praeger, 1964
Buku Teks