RT Journal Article SR Electronic JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 334 OP 334 DO 10.1183/09031936.04.00049604a VO 24 IS 2 A1 A.R. Leff YR 2004 UL http://erj.ersjournals.com/content/24/2/334.abstract AB