RT Journal Article SR Electronic T1 From the authors JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 446 OP 446 DO 10.1183/09031936.00149308 VO 33 IS 2 A1 J. R. Curtis YR 2009 UL http://erj.ersjournals.com/content/33/2/446.1.abstract AB