1. The University of Queensland; Primary Care Clinical Unit, Faculty of Medicine; Level 8, Health Sciences Building 16/910 Royal Brisbane & Women's Hospital Complex Brisbane Herston, Queensland Australia 4029
2. Cochrane; Cochrane Editorial Unit; St Albans House 57-59 Haymarket London UK SW1Y 4QX
3. The University of Newcastle; Discipline of General Practice, School of Medicine and Public Health; Newbolds Buiding, University of Newcastle, University Drive Newcastle Australia 2308
4. Severn Deanery; Bristol UK