RT Journal Article SR Electronic T1 Thorax online submission JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 1004 OP 1004 DO 10.1136/thorax.57.12.1004 VO 57 IS 12 YR 2002 UL http://thorax.bmj.com/content/57/12/1004.abstract AB