Coelho, Lia de Alencar, et al. “Evaluation of Oocyte Maturation Conditions and Bull Effect on the in Vitro Bovine Embryo Production”. Brazilian Journal of Veterinary Research and Animal Science, vol. 35, no. 3, Jan. 1998, pp. 120-2, https://doi.org/10.1590/S1413-95961998000300005.