1. Department of Pediatrics; Aalborg University Hospital; Aalborg Denmark
2. Childhood Cancer Research Unit; Department of Women's and Children's Health; Karolinska University Hospital and Karolinska Institute; Stockholm Sweden
3. Department of Pediatrics; Aarhus University Hospital; Aarhus Denmark
4. Departments of Pediatrics and Coagulation Disorders; University of Lund; University Hospital; Malmö Sweden
5. Department of Clinical Medicine; Aalborg University; Aalborg Denmark
6. Department of Pediatrics; Haukeland University Hospital; Bergen Norway
7. Children's Hospital; Landspitali University Hospital; Reykjavík Iceland
8. Children's Hospital and Department of Hematology; Cancer Center; Helsinki University Central Hospital; Helsinki Finland
9. Department of Oncohematology; Tallinn Children's Hospital; Tallinn Estonia
10. Center for Pediatric Oncology and Hematology; Children's Hospital; Affiliate of Vilnius University Hospital Santariskiu Klinikos; Vilnius Lithuania
11. Department of Pediatric Medicine; Oslo University Hospital; Rikshospitalet; Oslo Norway