RT Journal Article SR Electronic T1 Commentary: yet more to see down the bronchial tree? JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 226 OP 227 DO 10.1136/thx.51.2.226 VO 51 IS 2 A1 Hetzel, M. R. YR 1996 UL http://thorax.bmj.com/content/51/2/226.abstract AB