The Encyclopedia Americana : volume 30
Americana Corporation, 1977
 Buku Referensi
The Encyclopedia Americana : volume 30
Americana Corporation, 1964
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 30
Americana Corporation, 1960
 Buku Referensi
The encyclopedia American
Americana Corporation, 1980
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The Columbia encyclopedia
Columbia University Press, 1950
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