1. University of Hertfordshire; Centre for Research in Primary and Community Care; College Lane Hatfield Hertfordshire UK AL10 9PN
2. London School of Hygiene & Tropical Medicine; Cochrane Injuries Group; North Courtyard Keppel Street London UK WC1E 7HT
3. Department of Paediatrics; University of Cambridge School of Clinical Medicine; Box 116, Addenbrooks Hospital Hills Road Cambridge UK CB2 2QQ