RT Journal Article SR Electronic T1 Digest of Pneumoconiosis Statistics JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 112 OP 112 DO 10.1136/oem.29.1.112 VO 29 IS 1 A1 R. I. McCallum YR 1972 UL http://oem.bmj.com/content/29/1/112.1.abstract AB