ELOBIED, G. H. et al. Effect of production systems on the performance of dairy cows in the Gezira State, Sudan. Gezira Journal of Agricultural Science, [S.l.], v. 15, n. 2, dec. 2017. ISSN 1728-9556. Available at: <http://journals.uofg.edu.sd/index.php/gjas/article/view/981>. Date accessed: 25 june 2026.