RT Journal Article SR Electronic T1 AUTHORS' REPLY JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 150 OP 150 DO 10.1136/thx.46.2.150-c VO 46 IS 2 A1 Robert Miller A1 David Mitchell YR 1991 UL http://thorax.bmj.com/content/46/2/150.4.abstract AB