Christof Ebert, Vector Consulting Services, Germany, Christof.Ebert@vector-consulting.de
Gerald Heller, Hewlett-Packard, Germany, gerald.heller@hp.com
Sjaak Brinkkemper, Utrecht University, the Netherlands, s.brinkkemper@cs.uu.nl
Slinger Jansen, Utrecht University, the Netherlands, s.jansen@cs.uu.nl