Donald, Graeme, author
Simon & Schuster, 1994
Buku Referensi
Brewer, E. Cobham, author
New York, Harper Brothers
Buku Referensi
revised by Ivor H. Evans
Cassell & Company, 1975
Buku Referensi
Phythian, B. A., author
Hodder & Stoughton, 1993
Buku Referensi
Black, Henry Campbell, author
West Publishing, 1990
Buku Teks