RT Journal Article SR Electronic T1 Reply JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 80 OP 80 DO 10.1136/thx.40.1.80-b VO 40 IS 1 A1 PJ Brown YR 1985 UL http://thorax.bmj.com/content/40/1/80.3.abstract AB