Gill, Graeme, author
Cambridge University Press, 2015
Buku Teks
Gillispie, Charles Coulston, author
Princeton University Press, 1980
Buku Teks
Little, Brown & Co., 1982
Buku Teks
R. A. W. Rhodes [and others]
Open University press, 2003
Buku Teks
Stone, Geoffrey R.
Little, Brown and Company, 1991
Buku Teks