Quintero, Juan, H. Olguín, A. Quezada, H. Janacua, R. Rivas, and U. Macías. 2016. “Effect of HCG Application on Day 12 Post-Mating on the Reproductive Efficiency and Plasmatic Concentrations of Progesterone in Hair Ewes”. Cuban Journal of Agricultural Science 49 (4). https://www.cjascience.com/index.php/CJAS/article/view/491.