Pulmonary Disease, Chronic Obstructive

• National Heart and Lung Institute, Imperial College — London, United Kingdom

• Aarhus University Hospital — Aarhus, Denmark
• Esbjerg Hospital — Esbjerg, Denmark
• Regional Hospital Gødstrup — Herning, Denmark
• Silkeborg Regional Hospital — Herning, Denmark

• Capital Medical University — Beijing, Beijing Municipality, China

• Phoenix VA Health Care System, Phoenix, AZ — Phoenix, Arizona, United States
• VA Long Beach Healthcare System, Long Beach, CA — Long Beach, California, United States
• Rocky Mountain Regional VA Medical Center, Aurora, CO — Aurora, Colorado, United States
• Overton Brooks VA Medical Center, Shreveport, LA — Shreveport, Louisiana, United States

• Mayo Clinic Florida — Jacksonville, Florida, United States

• Teaching and Assistance Unit in Physiotherapy and Occupational Therapy — Belém, Pará, Brazil

• University of Miami — Miami, Florida, United States

Not specified

• Servicio de Neumología. Hospital Universitario Virgen de la Arrixaca. — Murcia, Spain

• Queen Mary Hospital — Hong Kong