Brennan, Lynne, author
Platkus, 1991
Buku Teks
Augusto Rinaldi
Crescent Books, 1985
Buku Referensi
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