1. Department of Pediatrics
2. Institute of Biometry and Statistics, University at Lübeck, Lübeck, Germany
3. Kinderklinik auf der Bult, Hannover, Germany
4. Olgahospital, Stuttgart, Germany
5. Department of Pediatrics, University of Greifswald, Greifswald, Germany
6. Children's Hospital Saarbrücken, Saarbrücken, Germany
7. Children's Hospital Kassel, Kassel, Germany
8. University of Cologne, Cologne, Germany
9. Kinderklinik St Hedwig, Regensburg, Germany
10. University of Aschaffenburg, Aschaffenburg, Germany