Silva, A. E. D. F. (1991) “Seasonal sexual activity of Nellore bulls and their cross-breed with Fleckvieh and Chianina: biometric testicular characteristics”, Pesquisa Agropecuaria Brasileira, 26(10), pp. 1745–1750. doi: 10.1590/S1678-3921.pab1991.v26.3521.