Machado, Rui, et al. “Service, Conception and Pregnancy Rates of Nelore Cows Treated With Human Corionic Gonadotropin and Estradiol-17² After Timed Artificial Insemination”. Brazilian Journal of Veterinary Research and Animal Science, vol. 45, no. 3, June 2008, pp. 221-30, https://doi.org/10.11606/issn.1678-4456.bjvras.2008.266700.