1. Computer Technology Institute and Press “Diophantus”, Patras, Greece & Computer Engineering and Informatics Dept., University of Patras, Patras, Greece
2. Computer Engineering and Informatics Department, University of Patras, Patras, Greece
3. University of Patras, Patras, Greece
4. Computer Technology Institute & Press “Diophantus”, Computer Engineering and Informatics Department, University of Patras, Patras, Greece