Professor Ian Sommerville, why on earth did you drop Ada? I can no more afford to recommend your book to my students. http://www.awlonline.com/product/0,2627,020139815X,00.html http://info.comp.lancs.ac.uk/computing/staff/person.phtml?member_id=002 -- Peter Hermann Tel+49-711-685-3611 Fax3758 [log in to unmask] Pfaffenwaldring 27 Raum 114, D-70569 Stuttgart Uni Computeranwendungen http://www.csv.ica.uni-stuttgart.de/homes/ph/ Team Ada: "C'mon people let the world begin" (Paul McCartney) Lucky