Fergusson, Rosalind, author
Routledge, 1994
Buku Referensi
Green, Jonathon, author
Cassell & Co, 2000
Buku Referensi
Phythian, B. A.
Hodder & Stoughton, 1986
Buku Referensi
The World Publishing Co., 1951
Buku Referensi
Encyclopaedia Britannica, 1981
Buku Referensi