Bull, John, author
Macmillan, 1991
Buku Teks
Cannadine, David
Papermac, 1996
Buku Teks
Easton, David, author
Prentice-Hall, 1965
Buku Teks
Butler, David
Radius Book/ Hutchinson, 1970
Buku Teks
Easton, David, author
New York, N. Y. Wiley 1967,
Buku Teks