1. a Department of Public Health Laboratories and Methodology, National Public Health Center, Albert Flórián út 2-6, Budapest 1097, Hungary
2. b World Health Organisation Regional Office for Europe, European Centre for Environment and Health, Platz der Vereinten Nationen 1, Bonn 53113, Germany
3. c Faculty of Health Sciences, Department of Public Health Sciences, Semmelweis University, Vas utca 17, Budapest 1088, Hungary