Institution: | 1. Addresses of authors: Department “Anatomy, Histology and Physiology”, Faculty of Veterinary Medicine, University of Forestry, 1756 Sofia, Kl. Ohridski 10, Bulgaria;2. Bulgarian Academy of Sciences, Institute of Biology and Immunology of Reproduction, 1113 Sofia, Tsarigradsko shose 73, Bulgaria;3. Department of Anatomy, Medical University, 1431 Sofia, Georgi Sofiiski 1, Bulgaria |