1. Neonatal Intensive Care Unit, Clínica Universidad de Navarra, Madrid
2. Neonatal Intensive Care Unit, AOU Policlinico G. Rodolico San Marco, Catania
3. Neonatal Intensive Care Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan
4. Department of Statistics and Operations Research, Faculty of Medicine, University of Cadiz, Cádiz
5. Department of Pediatrics, Clínica Universidad de Navarra, Pamplona
6. Neonatal Intensive Care Unit, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid
7. Neonatal Intensive Care Unit, Ospedale Regionale di Bolzano, Bolzano
8. Division of Pediatrics and Neonatology, Sandro Pertini Hospital, Rome
9. Division of Pediatrics and Neonatology, ASST del Garda, Desenzano del Garda (BS)
10. Neonatal Intensive Care Unit, Children's Hospital, ASST Spedali Civili, Brescia
11. Neonatal Intensive Care Unit, ASST Grande Ospedale Metropolitano Niguarda, Milan
12. Division of Neonatology, Area of Child Health, Department of Woman, Child Health and Public Health, Fondazione IRCCS Policlinico Universitario Agostino Gemelli, Rome
13. Neonatal Intensive Care Unit, Isola Tiberina Hospital Gemelli Isola, Rome