RT Journal Article SR Electronic T1 Adventitia JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 32 OP 32 DO 10.1136/thx.48.1.32 VO 48 IS 1 A1 T B Stretton YR 1993 UL http://thorax.bmj.com/content/48/1/32.abstract AB