F. A. de Oliveira, J. J. S. e Silva, L. Vilela, and D. martinhão G. de Sousa, “Doses and methods of potassium application on soybean in a cerrados soil of Bahia, Brazil”, PAB, vol. 27, no. 11, pp. 1485–1495, Nov. 1992, doi: 10.1590/S1678-3921.pab1992.v27.3795.