This author has not been identified. Look up 'Hendrik Drachsler' in GoogleThis author has not been identified. Look up 'Toine Bogers' in GoogleThis author has not been identified. Look up 'Riina Vuorikari' in GoogleThis author has not been identified. Look up 'Katrien Verbert' in GoogleThis author has not been identified. Look up 'Erik Duval' in GoogleThis author has not been identified. Look up 'Nikos Manouselis' in GoogleThis author has not been identified. Look up 'Günter Beham' in GoogleThis author has not been identified. Look up 'Stephanie N. Lindstaedt' in GoogleThis author has not been identified. Look up 'Hermann Stern' in GoogleThis author has not been identified. Look up 'Martin Friedrich' in GoogleThis author has not been identified. Look up 'Martin Wolpers' in Google