McEvery, Colin, author
Facts On File, 1979
Buku Referensi
edited by Geoffrey Barraclough
Times Books, 1984
Buku Referensi
McNally, Rand, author
Rand McNally & Co, 1957
Buku Referensi
rand McNally and Company, 2003
Buku Teks
Cribb, Robert, author
Nias Press/Det Kongelige Bibliotek, 2010
Buku Teks