Cook, Arthur N., author
Littlefield Adams, 1969
Buku Teks
Rooney, D.D., author
George G. Harrap, 1967
Buku Teks
Griffiths, Ieuan Ll., author
Routledge, 1994
Buku Teks
Howard University Press, 1993
Buku Teks
Stratton, Florence
Routledge, 1994
Buku Teks