The Encyclopedia Americana : the international reference work, volume 6
Americana Corporation, 1960
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 11
Americana Corporation, 1960
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 16
Americana Corporation, 1960
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 21
Americana Corporation, 1960
 Buku Referensi
The Encyclopedia Americana : the international reference work, volume 28
Americana Corporation, 1960
 Buku Referensi