1. Department of Pediatrics; Sahlgrenska Academy, University of Gothenburg; Gothenburg Sweden
2. Department of Women's and Children's Health; Karolinska Institutet and Astrid Lindgren Children's Hospital, Karolinska Hospital; Stockholm Sweden
3. Pediatric Department, St. Olavs Hospital; Trondheim University Hospital; Trondheim Norway
4. Children's Hospital; Helsinki University Central Hospital and University of Helsinki; Helsinki Finland
5. Children's Hospital; Landspítali University Hospital; Reykjavik Iceland
6. Children's Hospital; Affiliate of Vilnius University Hospital Santariskiu Klinikos and Vilnius University; Vilnius Lithuania
7. Department of Pediatrics; Aarhus University; Denmark
8. Department of Pediatrics and Adolescent Medicine; Rigshospitalet; Copenhagen Denmark
9. Department of Pediatrics; Skåne University Hospital; Lund Sweden