1. Hospital Universitari Dexeus , Barcelona , Spain
2. Neonatal Intensive Care Unit , G. d’Annunzio University , Chieti , Italy
3. Neonatal Intensive Care Unit , ASO SS Antonio, Biagio, C. Arrigo , Alessandria , Italy
4. Hospital Dr. Max Peralta Jimènez , Cartago , Costa Rica
5. Department of Pediatrics , University of Chieti , Chieti , Italy