Abou saq, F. M., and K. M. Ben Naser. “Genetic and Phenotypic Trends of Milk Production Traits in An Egyptien Friesian Herd”. The Libyan Journal of Agriculture, vol. 26, no. 1, June 2021, pp. 66-75, https://journals.uot.edu.ly/index.php/ljagric/article/view/2613.