Cheshire, G. C.
Butterworth, 1956
Buku Teks
Burnham, Scott J., author
The Michie Company, 1993
Buku Teks
Fuller, Lon L., author
West Publishing, 1964
Buku Teks
Scott, Robert E., author
Michie, 1988
Buku Teks
Bix, Brian H., author
Cambridge University Press, 2012
Buku Teks