RT Journal Article SR Electronic T1 The Determination of Toxic Substances in Air JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 229 OP 229 DO 10.1136/oem.13.3.229-a VO 13 IS 3 A1 W. N. Aldridge YR 1956 UL http://oem.bmj.com/content/13/3/229.2.abstract AB