Griffith, J.A.G.
University of Toronto Press , 1966
Buku Teks
Elcock, Howard, author
Routledge, 1994
Buku Teks
Stoker, Gerry, author
Macmillan, 1991
Buku Teks
Jackson, R.M. (Richard Meredith), 1903-1986, author
Macmillan, 1959
Buku Teks
Basil Blackwell, 1948
Buku Teks