1. Department of Paediatrics and Adolescent Medicine Aarhus University Hospital Aarhus Denmark
2. Pediatric Oncology Karolinska University HospitalStockholmSweden
3. Childhood Cancer Research Unit Department of Women´s and Children´s Health Karolinska Institutet Stockholm Sweden
4. Landspitali Children´s Hospital Reykjavík Iceland
5. Paediatrics TYKS Turku University Hospital Turku Finland
6. Department of Pediatrics Tromso University Hospital Tromso Norway
7. Department of Paediatrics and Adolescent Medicine University of Copenhagen, Institute of Clinical Medicine Faculty of Health and Medical Sciences Copenhagen University Hospital KobenhavnDenmark
8. Institute for Public Health Aarhus Universitet Research Unit for General Practice Aarhus Denmark