RT Journal Article SR Electronic T1 The Difficulty of Measuring the Measurable JF Respiratory Care FD American Association for Respiratory Care SP respcare.03380 DO 10.4187/respcare.03380 A1 Andreas Perren A1 Paolo Merlani YR 2014 UL http://rc.rcjournal.com/content/early/2014/06/03/respcare.03380.abstract AB