1. County Hospital, Târgu Jiu , Romania
2. “Carol Davila” University of Medicine and Pharmacy , Bucharest
3. Faculty of Sciences , University of Craiova , 200585 Craiova
4. “Tudor Vladimirescu” Hospital of Pneumology , Runcu, Gorj
5. “Marius Nasta” Institute of Pneumophtisiology , Bucharest