Lung Diseases, Obstructive

• Rigshospitalet — Copenhagen, Denmark
• Helsinki University Hospital — Helsinki, Finland
• Oslo University Hospital — Oslo, Norway
• Sahlgrenska Univ Hospital — Gothenburg, Sweden

Not specified

• National Jewish Health — Denver, Colorado, United States

• Karolinska Institutet — Stockholm, Sweden

• Oslo University Hospital and University of Oslo — Oslo, Norway

• Sanpasitthiprasong Hospital — Muaeng, Changwat Ubon Ratchathani, Thailand