1. Clinic for Endocrinology, Diabetes and Metabolism, University Pediatric Hospital, Medical University of Sofia, Sofia, Bulgaria
2. Department of Pediatrics, Medical University – Varna, Varna, Bulgaria
3. Clinic for Children's Diseases, University Hospital “George Stransky,” Medical University – Pleven, Pleven, Bulgaria
4. Clinic of Pediatrics and Genetic Diseases, UMBAL “St. George,” Medical University – Plovdiv, Plovdiv, Bulgaria
5. Medical Center in Pediatrics, Sofia, Bulgaria
6. Pediatric Clinic, Tokuda Hospital, Sofia, Bulgaria
7. Diagnosis – Consulting Center, Stara Zagora, Bulgaria