The New Encyclopaedia Britannica : volume 27
Encyclopaedia Britannica Inc., 2003
Buku Referensi
The New Encyclopaedia Britannica : volume 27
Encyclopaedia Britannica Inc., 1988
Buku Referensi
The New Encyclopaedia Britannica : volume 27, micropaedia konowledge in depth
Encyclopaedia Britannica Inc., 2002
Buku Referensi
The New encyclopaedia Britannica : volume 27, macropaedia knowledge in depth
Encyclopaedia Britannica Inc., 1998
Buku Referensi
The Encyclopedia Americana : volume 27
Americana Corporation, 1977
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