Pounds, Norman J. G.
Frederick A. Praeger, 1964
Buku Teks
rand McNally and Company, 2003
Buku Teks
Cribb, Robert
Nias Press/Det Kongelige Bibliotek, 2010
Buku Teks
London Chancellor Press 1999,
Buku Referensi
Philips
Chancellor Press, 1999
Buku Referensi