1. Institute of Respiratory Disease, Department of Medical and Occupational Sciences, Univeristy of Foggia, Italy.
2. Department of Medical Sciences, Section of Hygiene, University of Foggia, Foggia, Italyand Apulia Regional Epidemiological Observatory, Italy.
3. Department of Thoracic Surgery, Case di Cura Riunite, La Madonnina, Bari, Italy.