Authors
A. Nikolov
Institute for Scientific Research, Medical University, Pleven, Bulgaria
A. Blazhev
Division of Biology, Medical University, Pleven, Bulgaria
M. Tzekova
Department of Propedeutics of Internal Diseases, Medical University, Pleven, Bulgaria
K. Kostov
Department of Propedeutics of Internal Diseases, Medical University, Pleven, Bulgaria
N. Popovski
Department of Obstetrics and Gynaecology, Medical University, Pleven, Bulgaria