Ferreira, Sérgio Fernandes, et al. “Performance and Ruminal Metabolism in Beef Cattle in Grazing System in the Dry Period of Year Receiving Virginiamycin in the Diet”. Semina: Ciências Agrárias, vol. 36, no. 3Supl1, July 2015, pp. 2067-78, doi:10.5433/1679-0359.2015v36n3Supl1p2067.