RT Journal Article SR Electronic T1 Joint action of smoking and asbestos exposure on lung cancer JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 494 OP 495 DO 10.1136/oem.59.7.494-a VO 59 IS 7 A1 F D K Liddell YR 2002 UL http://oem.bmj.com/content/59/7/494.2.abstract AB