1. Division of Pediatric Critical Care UCSF Medical Centre San Francisco CA USA
2. Department of Neonatology University Hospital of Zurich Zurich Switzerland
3. Department of Epidemiology and Biostatistics UCSF San Francisco CA USA
4. Department of Neonatology University Children's Hospital Basel Basel Switzerland
5. Clinic of Neonatology University Hospital and University of Lausanne Lausanne Switzerland
6. Neonatal and Paediatric Intensive Care Unit Children's Hospital of Lucerne Lucerne Switzerland