1. HMU-Health and Medical University, Potsdam, Germany
2. Division Cystic Fibrosis, Clinic Westbrandenburg, Potsdam, Germany
3. Department of Paediatric Pneumology, Allergology, Cystic Fibrosis Center, Klinikum Westbrandenburg, Brandenburg a. d. Havel, Germany
4. University Hospital of the Brandenburg Medical School, Brandenburg a. d. Havel, Germany
5. Pneumology and Respiratory Medicine, Ernst von Bergmann Klinikum, Potsdam, Germany