Artikel Jurnal
Salzman, L.F., author
Oxford University Press, 1955
Buku Teks
Coote, Stephen, author
Penguin Group, 1988
Buku Teks
Lane-Poole, Stanley, 1854-1931, author
Methuen, 1968
Buku Teks
Southern, R.W. (Richard William), 1912-2001, author
Cresset Librar, 1967
Buku Teks