Ador, Lino Libo, and Abdel Moneim Mukhtar Abu Nikhaila. “Optimum Time of Insemination After Onset of Oestrus in Holstein – Friesian Dairy Cows in the Peri-Urban Khartoum (Sudan)”. Journal of Agricultural Studies, vol. 11, no. 3, Sept. 2023, pp. 38-52, doi:10.5296/jas.v11i3.21317.