1. Department of Biochemistry, Medical Faculty, University Nis, Nis, Serbia.
2. Department of Hygiene, Faculty of Physical culture, University Nis, Nis, Serbia.
3. Pediatric Clinic, Medical Faculty, University Nis, Nis, Serbia.
4. Medical Faculty, University Maribor, Maribor, Slovenia.
5. Clinic for Gynecology and Obstetrics, Clinical Center Nis, Nis, Serbia.