1. Department of Computer Science and Communication, Østfold University College, 1757 Halden, Norway
2. Department of Applied Informatics, University of Macedonia, 54636 Thessaloniki, Greece
3. Department of Education, University of Nicosia, 1700 Nicosia, Cyprus
4. Lenguajes y Sistemas Informáticos, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain
5. Escuela Técnica Superior de Ingenieros Informáticos, Universidad Politécnica de Madrid, 28660 Madrid, Spain