Lock, C. B. Muriel, author
Clive Bingley, 1972
Buku Referensi
Painter, Richard W., author
Pluto Press, 1993
Buku Teks
Manby, Chris, authror
Berkley, 2006
Buku Teks
Encyclopaedia Britannica Inc., 2002
Buku Referensi
Encyclopaedia Britannica Inc., 2002
Buku Referensi