1. Department of Educational and Social Policy, University of Macedonia, Thessaloniki, Greece
2. Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Greece
3. Study Center for the Visually Impaired (SZS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
4. School of Spatial Planning and Development, Aristotle University of Thessaloniki, Greece
5. Department of Education, Saint Mary-of-the-Woods College, Terre Haute, IN, USA