RT Journal Article SR Electronic T1 Introduction JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP S1 OP S1 DO 10.1136/thx.53.2008.S1 VO 53 IS suppl 3 A1 JOHN A FLEETHAM YR 1998 UL http://thorax.bmj.com/content/53/suppl_3/S1.abstract AB