Borges, Elias Nascentes, et al. “Effect of Lime and Gypsum on Calcium and Aluminum Amounts of the Compacted Layer of a Dark Red Latosol”. Pesquisa Agropecuaria Brasileira, vol. 32, no. 12, Dec. 1997, pp. 1309-15, doi:10.1590/S1678-3921.pab1997.v32.4786.