Using Computers to Negotiate and Explore Ideas: A Lognitudinal Study in a Greek Primary School C.T.I. Technical Report TR 94.06.34 - Γεωργιάδης, Παναγιώτης; Γυφτοδήμος, Γ.; Κυνηγός, Χρόνης (Computer Technology Institute Ινστιτούτο Τεχνολογίας Υπολογιστών Computer Science and Engineering Department, Patras University, 1994)