Lage, Luciana Andrade, et al. “Economic Feasibility of Adding Sunflower Oil to Elephant Grass-Based Diets of Lactating Dairy Cows”. Semina: Ciências Agrárias, vol. 37, no. 4Supl1, Sept. 2016, pp. 2313-20, doi:10.5433/1679-0359.2016v37n4Supl1p2313.