Q.Musurmonov, et al. “Productivity of Cows in the Experimental Group With Black-and-White and Its Crossbreeds With Holstein Bulls ”. Excellencia: International Multi-Disciplinary Journal of Education (2994-9521), vol. 1, no. 5, Nov. 2023, pp. 532-5, https://multijournals.org/index.php/excellencia-imje/article/view/151.