1. Laboratory of Physiology, School of Medicine, Democritus University of Thrace, Alexandroupolis, Greece,
2. Department of Gynecology and Obstetrics, University Clinic of Schleswig-Holstein, Campus Lubeck, Lubeck, Germany
3. Department of Obstetrics/Gynecology, Clinic of Kempten, Academic Teaching Hospital of the University of Ulm, Germany
4. Laboratory of Physiology, School of Medicine, Democritus University of Thrace, Alexandroupolis, Greece