Institution: | (1) Sleep Unit, GH G. Papanikolaou, Thessaloniki, Greece;(2) Sleep Centre, GH Sismanoglio, Athens, Greece;(3) Lab of Hygiene, Medical School, Democritus University of Thrace, Greece;(4) Sleep Unit, GH G. Papanikolaou, P.O. Box 50603, GR54013 Thessaloniki, Greece |