TY - JOUR T1 - Correction JF - British Journal of Industrial Medicine JO - Br J Ind Med SP - 216 LP - 216 DO - 10.1136/oem.7.4.216 VL - 7 IS - 4 A2 - , Y1 - 1950/10/01 UR - http://oem.bmj.com/content/7/4/216.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -