RT Journal Article SR Electronic T1 Inferring the quality of hospital treatment for COPD by mortality; caution is needed JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 897 OP 898 DO 10.1136/thoraxjnl-2013-203717 VO 68 IS 10 A1 M D L Morgan YR 2013 UL http://thorax.bmj.com/content/68/10/897.abstract AB