Zheliznyak , I., S. Voitenko, and T. Karunna. “Possibility of Increasing Dairy Productivity of Cows of Ukrainian Black-Spotted Dairy Breed Due to Breeding and Technological Factors. ”. Bulletin of Sumy National Agrarian University. The Series: Livestock, no. 4(39), Dec. 2019, pp. 49-56, doi:10.32845/bsnau.lvst.2019.4.7.