RT Journal Article SR Electronic T1 Mechanisms of adverse effects of β-agonists in asthma JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 739 OP 741 DO 10.1136/thx.2009.119230 VO 64 IS 9 A1 Sebastian L Johnston A1 Michael R Edwards YR 2009 UL http://thorax.bmj.com/content/64/9/739.abstract AB