[1] Sundby Hosp, Dept Resp Med, S-97180 Lulea, Sweden
[2] Karolina Hosp, Dept Pulmonol & Allergol, Mosonmagyarovar, Hungary
[3] Sahlgrens Univ Hosp, Dept Resp Med & Allergol, Gothenburg, Sweden
[4] Szazhalom Outpatient Polyclin, Szazhalombatta, Hungary