1. Clinic of Rheumatology, Pediatric University Hospital SBALDB “Prof. Ivan Mitev”, Medical University of Sofia, Sofia, Bulgaria
2. Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, Sofia, Bulgaria
3. Department of Pediatric Cardiology, National Cardiology Hospital, Sofia, Bulgaria
4. Clinic of Nephrology, Pediatric University Hospital SBALDB “Prof. Ivan Mitev”, Medical University of Sofia, Sofia, Bulgaria