Цвігун, А. Т., and О. А. Цвігун. “THE AVAILABILITY OF MACROELEMENTS AND PRODUCTIVINI OF COWS AT DIFERENT LEVELS OF PROTEIN SUPPLY”. Podilian Bulletin: Agriculture, Engineering, Economics, vol. 1, no. 24, Jan. 2016, pp. 215-21, http://pb.pdatu.edu.ua/article/view/136241.