FERRAZ, G. A. E S.; DA SILVA, F. M.; DE OLIVEIRA, M. S.; AVELAR, R. C.; SALES, R. S. Spatial vatiability of the dosage of P2O5 and K2O tofertilize in variable rate and in a conventional way in a coffee field. Coffee Science - ISSN 1984-3909, v. 10, n. 3, p. 346 - 356, 4 Aug. 2015.