Evangelista, Cristiano Ramos, et al. “Enzymatic Activity of Soil under Organic and Conventional Management in the Culture of Sugar Cane in Goiás”. Semina: Ciências Agrárias, vol. 33, no. 4, Aug. 2012, pp. 1251-62, doi:10.5433/1679-0359.2012v33n4p1251.