RT Journal Article SR Electronic T1 Radioactivity JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 327 OP 328 DO 10.1136/oem.21.4.327-c VO 21 IS 4 A1 G. E. Harrison YR 1964 UL http://oem.bmj.com/content/21/4/327.4.abstract AB