VENEGAS, V. H. A.; GUIMARÃES, P. T. G.; FREIRE, F. M. Optimum relative concentrations of phosphorus and sulfur in coffee fertilization in a Dark-Red Latosol, at Machado, MG, Brazil. Pesquisa Agropecuaria Brasileira, v. 22, n. 4, p. 359–365, 17 Apr.2014.