Enciclopedia garzanti universale : vol. 1, A-N
Garzanti, 1962
Buku Referensi
The World book encyclopedia : volume 13, N-O
Field Enterprises Educational Corporation, 1963
Buku Referensi
Encyclopedia of knowledge : volume 1
Grolier Incorporated, 1991
Buku Referensi
Ensiklopedi Indonesia; Jilid 1
Ichtiar Baru-Van Hoeve, 1980
Buku Referensi
The Encyclopedia Americana : volume 1
Americana Corporation, 1977
Buku Referensi