1. Van Creveldkliniek; Department of Hematology; University Medical Center; Utrecht The Netherlands
2. Heamophilia Center; Department of Haematology; Great Ormond Street Hospital for Children; London UK
3. Paediatric Department of Coagulation Disorders; Karolinska University Hospital; Stockholm Sweden
4. Child Development and Exercise Center; Wilhelmina Children's Hospital; University Medical Center; Utrecht The Netherlands
5. Dr. von Haunersches Children's Hospital; University of Munich; Munich Germany
6. Julius Center for Health Sciences and Primary Care; University Medical Center; Utrecht The Netherlands