1. Center for Sleep and Vigilance Disorders Sahlgrenska Academy Gothenburg University Gothenburg Sweden
2. Center of Sleep Medicine, CC12 University Hospital Charité Berlin Germany
3. Sleep Disorders Centre Department of Respiratory Medicine Sahlgrenska University Hospital Gothenburg Sweden
4. Department of Respiratory Medicine, Allergology and Sleep Medicine Nuremberg General Hospital Paracelsus Medical University Nurenberg Germany
5. Department of Pulmonary Medicine Bethanien Hospital Solingen Germany
6. Department of Pulmonary Medicine Agaplesion Bethesda Krankenhaus Wuppertal Wuppertal Germany