1 Department of Health Economics, Medical School, National and Kapodistrian University of Athens, 75, M. Assias Street, 11527, Athens, Greece. karafedis@yahoo.gr.
2 Department of Business Administration, University of Macedonia, Thessaloniki, Greece.
3 Department of Health Economics, Medical School, National and Kapodistrian University of Athens, 75, M. Assias Street, 11527, Athens, Greece.