MARTÍNEZ, G. A.; BOULDIN, D. R. An alternative method for determination of cations in solution of small soil samples. The Journal of Agriculture of the University of Puerto Rico, [S. l.], v. 75, n. 3, p. 223–231, 1991. DOI: 10.46429/jaupr.v75i3.3590. Disponível em: https://revistas.upr.edu/index.php/jaupr/article/view/3590. Acesso em: 27 jun. 2022.