1. Department of Pulmonology, University General Hospital of Alexandroupolis, Alexandroupoli, Greece
2. Respiratory Medicine Department, School of Medicine, University of Ioannina, Ioannina, Greece
3. Medical Department, ELPEN Pharmaceutical Co. Inc, Pikermi, Attica
4. Pulmonary Clinic, Hygeia Hospital, Marousi, Athens
5. Primary Healthcare Center of Moires, Heraklion, Greece