This research has been done using mainly the following encyclopaedia:
Britannica 2001 and 2002.
Compton's Interactive Encyclopedia (1998 edition).
Encarta 98 (Microsoft).
Encyclopédie Générale (French).
Hutchinson Encyclopedia 2001.
New Millenium Encyclopedia (Webster Gold).
Oxford Interactive (version 1.0).
Webster Concise Interactive Encyclopedia.
Webster World Encyclopedia 2001.
World Book 2001.