1. Pain Research and Nuffield Division of Anaesthetics; University of Oxford; The Churchill; Oxford U.K
2. Peninsula Medical School; University of Exeter; Exeter U.K
3. Department of Occupational, Social and Environmental Medicine; University Medical Center Göttingen; Göttingen Germany
4. Swansea Centre for Health Economics; College of Human and Health Sciences; Swansea University; Swansea U.K