E.C. Young
Allen Lane, 1979
Buku Referensi
Peter, author
Penguin, 1978
Buku Referensi
Thomas, Merlin, author
Penguin Books, 1985
Buku Referensi
Whitten, D.G.A., 1921-, author
Penguin Books, 1972
Buku Referensi
Whittow, John B., author
Allen Lane, 1984
Buku Referensi