Encyclopedia of knowledge : volume 18
Grolier Incorporated, 1991
Buku Referensi
The Encyclopedia Americana : volume 18
Grolier, 1994
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The Encyclopedia Americana : volume 18
Americana Corporation, 1977
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Collier's encyclopedia; Volume 18
Macmillan, 1990
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Grolier family encyclopedia : volume 18
Grolier Incorporated, 1995
Buku Referensi