1. Department of Pediatric Oncology; Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University; Duesseldorf; Germany
2. Institute of Medical Informatics; University of Muenster; Germany
3. Department of Pediatric Hematology and Oncology; University of Essen; Germany
4. Department of Pediatric Hematology and Oncology; University of Bonn; Germany