Budworth, Geoffrey, author
Chancellor Press , 1997
Buku Referensi
Maxwell-Hudson, Clare, author
Dorling Kindersley, 1988
Buku Referensi
Flast, Robert, author
Berkely, California Osborne McGraw-Hill 1986,
Buku Teks
Harberts, Kurt, author
Frederick A. Preager, 1963,
Buku Teks
Brown, Neville, author
Pan Books, 1970
Buku Teks