1. European Monitoring Centre for Drugs and Drug Addiction; Interventions, Best Practice and Scientific Partners; Cais do Sodre' 1249-289 Lisbon Lisbon Portugal
2. Lazio Regional Health Service; Department of Epidemiology; Via di Santa Costanza, 53 Rome Italy 00199
3. ASL RM/E; Department of Epidemiology; Via di Santa Costanza, 53 Rome Italy 00198