Encyclopedia of knowledge : volume 9
Grolier Incorporated, 1991
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The Encyclopedia Americana : volume 9
Americana Corporation, 1977
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The Encyclopedia Americana : volume 9
Americana Corporation, 1964
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Encyclopaedia Britannica : volume 9
Encyclopaedia Britannica Inc., 1967
Buku Referensi
Encyclopaedia Britannica : volume 9
Encyclopaedia Britannica Inc., 1968
Buku Referensi