RT Journal Article SR Electronic T1 Author's response: Airway anatomy in COPD: many dimensions to consider JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 585 OP 585 DO 10.1136/thoraxjnl-2014-206606 VO 70 IS 6 A1 Benjamin M Smith A1 Eric A Hoffman A1 R Graham Barr YR 2015 UL http://thorax.bmj.com/content/70/6/585.abstract AB