TY - JOUR T1 - Professor J. A. Birkbeck replies as follows JF - Archives of Disease in Childhood JO - Arch Dis Child SP - 252 LP - 253 DO - 10.1136/adc.52.3.252-a VL - 52 IS - 3 AU - J. A. Birkbeck Y1 - 1977/03/01 UR - http://adc.bmj.com/content/52/3/252.2.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -