%0 Conference Paper %B Second Hellenic Conference on Artificial Intelligence, SETN 02 %D 2002 %T Roles in Collaborative Activity %A I. Partsakoulakis %A G. Vouros %E I. Partsakoulakis %B Second Hellenic Conference on Artificial Intelligence, SETN 02 %I LNCS - Springer Verlag %C Thessaloniki, Greece %8 00/2002