1. COPD Center, Sahlgrenska University Hospital, Institute of MedicineUniversity of Gothenburg Gothenburg Sweden
2. CIRO Horn The Netherlands
3. Institute for Pulmonary Rehabilitation ResearchSchoen Klinik Berchtesgadener Land Schoenau am Koenigssee Germany
4. Department of Prevention, Rehabilitation and Sports MedicineTechnical University of Munich Munich Germany