RT Journal Article SR Electronic T1 Ask the Expert: Lung function measurement JF Breathe JO Breathe FD European Respiratory Society SP 224 OP 226 DO 10.1183/18106838.0503.224 VO 5 IS 3 A1 M. Agnew YR 2009 UL http://breathe.ersjournals.com/content/5/3/224.abstract