1. Medisch Spectrum Twente; Department of Pulmonary Medicine; Enschede Netherlands
2. University of Twente; Department of Health Technology and Services Research, Faculty of Behavioural Sciences; Enschede Netherlands
3. Flinders University; School of Medicine; Adelaide Australia
4. Repatriation General Hospital; Department of Respiratory Medicine; Adelaide Australia
5. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care; PO Box 85500 Utrecht Netherlands
6. University of Twente; Department of Research Methodology, Measurement, and Data-Analysis, Faculty of Behavioral Sciences; Haaksbergerstraat 55 Enschede Netherlands