1. Paediatric Haematology and Oncology; University Children's Hospital; Münster Germany
2. Pathology; Haematopathology Section and Lymph Node Registry; Christian-Albrechts-University Kiel and University Hospital Schleswig-Holstein; Kiel Germany
3. Paediatric Haematology and Oncology; Justus Liebig University; Giessen Germany
4. Paediatric Haematology and Oncology; Medical School Hannover; Hannover Germany
5. Paediatric Haematology and Oncology; University Hospital; Zurich Switzerland
6. Paediatric Haematology and Oncology; St. Anna Children's Hospital; Medical University of Vienna; Vienna Austria
7. Paediatric Haematology and Oncology; University Hospital; Prague Czech Republic