1. Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier
2. 4 F-34095 Montpellier
3. France
4. CNR-ISC UOS Roma, c/o Dipartimento di Fisica, Sapienza Università di Roma
5. 00185 Roma
6. Italy
7. Dipartimento di Fisica, Sapienza Università di Roma
8. National Institute for Insurance against Accidents at Work (INAIL Research), Department of Occupational and Environmental Medicine, Epidemiology and Hygiene
9. Roma