Khadr Sophie N, Viner Russell M, Goddard Andrea
General and Adolescent Paediatrics, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
Arch Dis Child. 2011 Nov;96(11):991-4. doi: 10.1136/archdischild-2011-300185. Epub 2011 Jul 19.