RT Journal Article SR Electronic T1 Asthma and poverty JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 239 OP 244 DO 10.1136/thorax.55.3.239 VO 55 IS 3 A1 Rona, Roberto J YR 2000 UL http://thorax.bmj.com/content/55/3/239.abstract AB