1. Department of Paediatric Pneumology & Immunology; Charité - Universitätsmedizin Berlin; Berlin Germany
2. Department of Statistical Sciences “Paolo Fortunati”; University of Bologna; Bologna Italy
3. Department of Statistical Sciences; Università “La Sapienza”; Roma Italy
4. Department of Pediatrics; Technical University of Munich; Munich Germany
5. Department of Pediatrics St. Hedwig; St. Josefs Hospital; Freiburg Germany
6. Department of Pediatrics and Adolescent Medicine; University Medicine Mainz; Mainz Germany
7. Department of Pediatrics; Heinrich-Heine-University; Düsseldorf Germany
8. Institute for Social Medicine, Epidemiology and Health Economics; Charité - Universitätsmedizin Berlin; Berlin Germany
9. Institute of Clinical Epidemiology and Biometry; University of Würzburg; Würzburg Germany