RT Journal Article SR Electronic T1 Authors’ reply JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 291 OP 291 VO 63 IS 3 A1 P Aveyard A1 M Munafo A1 M Murphy A1 E Johnstone YR 2008 UL http://thorax.bmj.com/content/63/3/291.2.abstract AB