RT Journal Article SR Electronic T1 British Occupational Hygiene Society JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 152 OP 153 DO 10.1136/oem.13.2.152 VO 13 IS 2 YR 1956 UL http://oem.bmj.com/content/13/2/152.abstract AB