1. University of Oxford; Pain Research and Nuffield Department of Clinical Neurosciences; Pain Research Unit, Churchill Hospital Oxford University Hospitals Oxford Oxfordshire UK OX3 7LE
2. University Medical Center Göttingen; Department of Occupational, Social and Environmental Medicine; Waldweg 37 B Göttingen Germany D-37073
3. University of Adelaide; School of Nursing; North Terrace Adelaide South Australia Australia 5000
4. University of Oxford; Nuffield Department of Obstetrics and Gynaecology; The Fetal Medicine Unit, Level 6, Women's Centre John Radcliffe Hospital Oxford Oxfordshire UK OX3 9DU