RT Journal Article SR Electronic T1 Review Article JF Archives of Disease in Childhood JO Arch Dis Child FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 109 OP 115 DO 10.1136/adc.39.204.109 VO 39 IS 204 A1 H. H. Nixon YR 1964 UL http://adc.bmj.com/content/39/204/109.abstract AB