Souza, Igor Alexandre de, et al. “Forage Mass, Chemical Composition and Leaf Chlorophyll Index of Signal Grass and Organic Matter in Soil under Increasing Levels of Nitrogen”. Semina: Ciências Agrárias, vol. 37, no. 3, June 2016, pp. 1505-14, doi:10.5433/1679-0359.2016v37n3p1505.