N.V. Douglas, Chairman
A.R. Shearer, 1975
Buku Teks
Obrien, Greg
Heinemann Reed, 1988
Buku Teks
Thakur, Ramesh
London: Westview Press, 1986,
Buku Referensi
University of California Press, 1947
Buku Teks
Barber, Laurie
Century Hutchinson, 1989
Buku Teks