1. NICU Nikaia General Hospital “Agios Panteleimon”, Piraeus, Greece
2. Neonatal Department, National and Kapodistrian University of Athens, Aretaeio Hospital, Athens, Greece
3. NICU, University Hospital of Larissa, Larissa, Greece
4. Laboratory of Haematology and Blood Bank Unit, “Attiko” Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece