Whittow, John B., author
Allen Lane, 1984
Buku Referensi
Goodall, Brian, author
Penguin Books, 1987
Buku Referensi
Moore, W. G., author
Penguin Books, 1974
Buku Referensi
Bannock, G., author
Penguin Books, 1974
Buku Referensi
Thomas, Merlin, author
Penguin Books, 1985
Buku Referensi