Encyclopaedia Britannica : volume 6
Encyclopaedia Britannica Inc., 1967
 Buku Referensi
Encyclopaedia Britannica : volume 6
Encyclopaedia Britannica Inc., 1968
 Buku Referensi
The Australian encyclopaedia : volume 6
Grolier Society of Australia, 1983
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Encyclopaedia universalis : volume 6
Encyclopaedia Universalis France S.A. , 1989
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The New Encyclopaedia Britannica : volume 6
Encyclopaedia Britannica Inc., 1988
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