@article{article206e30af,
title   = {Modal analysis to estimate the composition of single superphosphates},
author = {Prochnow, Luís Ignácio and Dillard, E. F. and Austin, E. R. and Chien, S. H. and Calvo, C. G.},
year = {2003},
journal   = {Communications in Soil Science and Plant Analysis}
}