Kidron, Michael, author
Simon & Schuster, 1984
Buku Teks
Lye, Keith, author
The Royal Geographical Society, 2000
Buku Referensi
Debenham, Frank, author
Reader's Digest Association, 1979
Buku Referensi
Pergamon Press, 1968
Buku Referensi
edited by B.M. Willet
George Philip and Son, 1981
Buku Referensi