1. National Sports Academy “Vassil Levski”, 21 Akad. Stefan Mladenov St., Studentski Grad, 1700 Sofia, Bulgaria
2. Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Akad. G. Bonchev St., bl. 103A, 1113 Sofia, Bulgaria
3. Laboratory of Free Radical Processes, Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Akad. G. Bonchev St., 1113 Sofia, Bulgaria
4. Department of Synaptic Signaling and Communication, Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Akad. G. Bonchev St., 1113 Sofia, Bulgaria
5. Department of Anatomy, Faculty of Medicine, Trakia University, 11 Armejska St., 6000 Stara Zagora, Bulgaria
6. Department of Anatomy, Histology, General and Clinical Pathology and Forensic Medicine, Faculty of Medicine, Sofia University St. Kl. Ohridski, Lozenets University Hospital, 1 Koziak St., 1000 Sofia, Bulgaria