RT Journal Article SR Electronic T1 Lung clearance index: should we really go back to nitrogen washout? JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 655 OP 656 DO 10.1183/09031936.00069913 VO 43 IS 2 A1 Jørgen G. Nielsen YR 2014 UL http://erj.ersjournals.com/content/43/2/655.abstract AB