1. Agricultural Research Council; CRA Ex-INRAN; Rome; Italy
2. Unit of Hygiene and Epidemiology; Department of Biological and Medical Sciences, University of Udine; Udine; Italy
3. Department of Epidemiology; Istituto di Ricerche Farmacologiche Mario Negri-IRCCS; Milan; Italy
4. Unit of Epidemiology and Biostatistics; Centro di Riferimento Oncologico; Aviano; Italy