RT Journal Article SR Electronic T1 From the authors: JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 780 OP 781 DO 10.1183/09031936.00068909 VO 34 IS 3 A1 S. S. Hwang A1 J-J. Yim YR 2009 UL http://erj.ersjournals.com/content/34/3/780.2.abstract AB