So many links to so many things that the mind boggles. http://www.geometry.net/index. Advantage over eg raw Google search on your favourite subject is that the links are hierarchically ordered and many references to eg books have abstracts. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads