1. Department of Neonatology, Faculty of Medicine, Pediatric Hospital “Iv. Mitev”, Medical University of Sofia, 1612 Sofia, Bulgaria
2. Department of Organisation and Economics of Pharmacy, Faculty of Pharmacy, Medical University of Sofia, 1000 Sofia, Bulgaria
3. Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 1000 Sofia, Bulgaria