1. Lero, School of Computing, Dublin City University, Glasnevin Campus, Dublin, Ireland, Anghelos Centro Studi sulla Comunicazione, Palermo and Italy, --- Select a Country ---
2. Dipartimento di Matematica e Informatica, Università di Palermo, Palermo and Italy, --- Select a Country ---
3. Istituto per le Tecnologie Didattiche, Consiglio Nazionale delle Ricerche, Palermo and Italy, --- Select a Country ---
4. Lero, School of Computing, Dublin City University, Glasnevin Campus, Dublin and Ireland, --- Select a Country ---