Pereira, João, et al. “Levels of Zinc Sulfate in Field Corn ( Zea Mays ) Grown in Campo-Cerrados”. Pesquisa Agropecuaria Brasileira, vol. 8, no. 7, Apr. 2014, pp. 187-91, https://doi.org/10.1590/S1678-3921.pab1973.v8.17524.