Rossi, Renzo, author
Macmillan, 1996
Buku Referensi
Shepperd, William R., author
Barnes and Noble, 1959
Buku Referensi
Rand McNally & Company, 1952
Buku Referensi
Cribb, Robert, author
Nias Press/Det Kongelige Bibliotek, 2010
Buku Teks
The George F. Cram, 1952
Buku Referensi