1. Rush University Medical Center, Chicago, IL, USA
2. AO Research Institute, Davos, Switzerland
3. Oulu University Hospital and University of Oulu, Oulu, Finland;
4. Finnish Institute of Occupational Health, Oulu, Finland
5. Ganga Hospital, Coimbatore, Tamil Nadu, India
6. Pontificia Universidade Catolica do Paraná, Curitiba, Brazil
7. University of Southern California, Los Angeles, CA, USA
8. Radboud University Medical Centre, Nijmegen, Netherlands