RT Journal Article SR Electronic T1 Changes in the Lungs Produced by Natural Graphite JF British Journal of Industrial Medicine JO Br J Ind Med FD BMJ Publishing Group Ltd SP 91 OP 99 DO 10.1136/oem.6.2.91 VO 6 IS 2 A1 Harding, H. E. A1 Oliver, G. B. YR 1949 UL http://oem.bmj.com/content/6/2/91.abstract AB