1. Professor, Clinic of Neurosurgery, St. George University Hospital, Plovdiv, Bulgaria
2. Associate Professor, Department of Neurosurgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria
3. Assistant Professor, Department of Neurosurgery, Faculty of Medicine, Medical University of Plovdiv, Plovdiv, Bulgaria
4. Professor, Department of Anatomy, Histology and Embryology, Medical Faculty, Medical University of Plovdiv, Plovdiv, Bulgaria