Risk factors for forced expiratory volume in 1 s decline in European patients with cystic fibrosis: data from the European Cystic Fibrosis Society Patient Registry oleh Elpis Hatziagorou, Steffen Fieuws, Annalisa Orenti, Lutz Naehrlich, Uros Krivec, Meir Mei-Zahav, Andreas Jung, Kris De Boeck, on behalf of the ECFSPR Collaborative Group, Pfleger Andreas