1. Department of General Pediatrics, Neonatology, and Pediatric Cardiology; University Children's Hospital Duesseldorf; Duesseldorf Germany
2. Department of Women's and Children's Health; University of Padova; Padova Italy
3. Unit for Pulmonary Diseases; University Children's Hospital Ljubljana; Ljubljana Slovenia
4. 3rd Pediatric Department; “Attikon” University General Hospital; Haidari-Athens Greece
5. Pediatric Department; Medical University of Graz; Graz Austria
6. Pediatric Department; Charles University Prague and University Hospital Motol; Prague Czech Republic