RT Journal Article SR Electronic T1 Breathing techniques in the management of asthma JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 835 OP 835 VO 62 IS 9 A1 van der Wouden, Johannes C A1 Verhagen, Arianne P YR 2007 UL http://thorax.bmj.com/content/62/9/835.1.abstract AB