1. Department of Pulmonary Medicine; Medisch Spectrum Twente; Enschede The Netherlands
2. Department of Pulmonology; University of Groningen, and University Medical Center Groningen; Groningen The Netherlands
3. Department of Research Methodology, Measurement and Data Analysis; University Twente; Enschede The Netherlands
4. Department for Health Evidence; Radboud University Medical Center; Nijmegen The Netherlands
5. Southern Adelaide Local Health Network; Respiratory Research Unit; Repatriation General Hospital; Daw Park South Australia Australia
6. School of Medicine; Flinders University; Adelaide South Australia Australia