Spehar, Carlos Roberto. “Mineral Composition of Soya Beans Cultivated in a Cerrado Acid Soil, With Two Levels of Liming”. Pesquisa Agropecuaria Brasileira, vol. 28, no. 5, May 1993, pp. 645-8, doi:10.1590/S1678-3921.pab1993.v28.3922.