1. Department of Occupational Medicine, University General Hospital of Alexandroupolis, Alexandroupolis, Greece
2. Laboratory of Hygiene and Environmental Protection, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
3. Department of Pneumonology, University General Hospital of Alexandroupolis, Alexandroupolis, Greece
4. Medical School, Democritus University of Thrace, Alexandroupolis, Greece