Amedée Bonnet, J. and Villamil, F.A. 1933. RESEARCH ON SHORTENING TIME WITHOUT AFFECTING THE ACCURACY OF DYER’S MODIFIED METHOD FOR THE DETERMINATION IN SOILS, OF PHOSPHORIC ACID, LIME AND POTASH SOLUBLE IN CITRIC ACID SOLUTION (1 PER CENT). The Journal of Agriculture of the University of Puerto Rico. 17, 4 (Oct. 1933), 287–300. DOI:https://doi.org/10.46429/jaupr.v17i4.14258.