1. Department of Medical Informatics; Erasmus University Medical Centre; Rotterdam; The Netherlands
2. Health Search; Italian College of General Practitioners; Florence; Italy
3. Primary Care & Public Health Sciences; Kings College London; London; UK
4. Department of Clinical and Experimental Medicine and Pharmacology; University of Messina; Messina; Italy
5. Department of Epidemiology; Harvard School of Public Health; Boston; MA; USA