The Encyclopedia Americana : volume 20
Grolier, 1994
Buku Referensi
The Encyclopedia Americana : volume 20
Americana Corporation, 1977
Buku Referensi
The Encyclopedia Americana : volume 20
Americana Corporation, 1964
Buku Referensi
Collier's encyclopedia : volume 20
Macmillan Educational Company, 1990
Buku Referensi
Grolier family encyclopedia : volume 20
Grolier Incorporated, 1995
Buku Referensi