1. Institute of Environmental and Occupational Toxicology, Airolo, Switzerland;
2. Walther-Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, München, Germany;
3. Finnish Institute of Occupational Health, Helsinki, Finland;
4. Department of Environmental and Occupational Medicine, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, UK;
5. Institute of Occupational Medicine, Chinese Academy of Preventive Medicine, Beijing, PR China