Gasperin, B.G. et al. 2011. Intravaginal progestagen for estrus and parturition control in sows. Pesquisa Agropecuaria Brasileira. 46, 8 (Oct. 2011), 961–964. DOI:https://doi.org/10.1590/S1678-3921.pab2011.v46.10294.