Casagrande, João Floriano, et al. “A Discriminant Function for Qualification of Zebu Semen Samples before Freezing”. Pesquisa Agropecuaria Brasileira, vol. 11, no. 5, Apr. 2014, pp. 25-28, doi:10.1590/S1678-3921.pab1976.v11.16883.