Ferreira, G. B.; Fontes, R. L. F.; Venegas, V. H. A.; Fontes, M. P. F.; Pereira, J. M. N. Interference of Iron on Soil Boron Determination With Azomethine-H in Acid Solutions. PAB 2002, 37 (9), 1311-1318. https://doi.org/10.1590/S1678-3921.pab2002.v37.6471.