RT Journal Article SR Electronic T1 Upgrading home heating systems improved subjective symptoms in children with asthmaCommentary JF Evidence Based Nursing JO Evid Based Nurs FD BMJ Publishing Group Ltd and RCN Publishing Company Ltd SP 42 OP 42 DO 10.1136/ebn.12.2.42 VO 12 IS 2 A1 Sandra Small YR 2009 UL http://ebn.bmj.com/content/12/2/42.abstract AB