Araújo, P. G.; Pizelli, G. N.; Carvalho, M. R. de; Resende, O. de A.; Britto, D. P. P. de S. Influence of Estrogen in Fertility of “problem" Cows (repeat-Breeding). PAB 2014, 6 (1), 131-135. https://doi.org/10.1590/S1678-3921.pab1971.v6.17746.