Beauchamp, Tom L., author
Oxford University Press, 1994
Buku Teks
Skegg, P. D. G., author
Oxford Clarendon Press , 1984
Buku Teks
Downie, R.S
Oxford University Press, 1994
Buku Teks
Sokol, Daniel K.
Springer, 2012
eBooks
Scully, Thomas J., 1932-, author
Simon and Schuster, 1987
Buku Teks