The Encyclopedia Americana : volume 6
Grolier, 1994
 Buku Referensi
The Encyclopedia Americana : volume 6
Americana Corporation, 1977
 Buku Referensi
The Encyclopedia Americana : volume 6
Americana Corporation, 1964
 Buku Referensi
Collier's encyclopedia : volume 6
Macmillan Educational Company, 1990
 Buku Referensi
Grolier family encyclopedia : volume 6
Grolier Incorporated, 1995
 Buku Referensi