The New Encyclopaedia Britannica : volume 17, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
 Buku Referensi
The New Encyclopaedia Britannica : volume 22, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
 Buku Referensi
The New Encyclopaedia Britannica : volume 29, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
 Buku Referensi
The New Encyclopaedia Britannica : volume 13, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
 Buku Referensi
The New Encyclopaedia Britannica : volume 14, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
 Buku Referensi