Kidron, Michael
Simon & Schuster, 1984
Buku Teks
Lye, Keith
The Royal Geographical Society, 2000
Buku Referensi
Pergamon Press, 1968
Buku Referensi
edited by B.M. Willet
George Philip and Son, 1981
Buku Referensi
edited by Andrew Heritage
Dorling Kindersley, 2000
Buku Referensi