1. Division of Pulmonary and Critical Care Medicine Department of Medicine Kyung Hee University Seoul Korea
2. Division of Pulmonary, Allergy and Critical Care Medicine Department of Internal Medicine Hallym University Sacred Heart Hospital Hallym University College of Medicine Anyang Korea
3. Division of Pulmonary, Allergy and Critical Care Medicine Department of Internal Medicine Konkuk University School of Medicine Seoul Korea
4. Division of Pulmonary and Critical Care Medicine Hanyang University Guri Hospital Hanyang University College of Medicine Guri Korea
5. Division of Pulmonary, Allergy and Critical Care Medicine Department of Internal Medicine Hallym University Chuncheon Sacred Heart Hospital Hallym University College of Medicine Anyang Korea
6. Division of Pulmonary, Critical Care and Sleep Medicine Department of Internal Medicine St Paul's Hospital College of Medicine The Catholic University of Korea Seoul Korea
7. Regional Center for Respiratory Disease Yeungnam University Medical Center Yeungnam University College of Medicine Daegu Korea
8. Division of Respiratory and Critical Care Medicine Department of Internal Medicine College of Medicine Korea University Seoul Korea
9. Division of Pulmonary and Critical Care Medicine Department of Internal Medicine Yeouido St Mary's Hospital College of Medicine The Catholic University of Korea Seoul Korea
10. Division of Pulmonary, Allergy and Critical Care Medicine Department of Internal Medicine Seoul St Mary's Hospital College of Medicine The Catholic University of Korea Seoul Korea