Hernández-Medina, E., and M. A. Lugo-López. “Observations on the Boron-Manganese Relationships in Soybean and Corn Plants”. The Journal of Agriculture of the University of Puerto Rico 42, no. 1 (January 1, 1958): 27–34. Accessed December 21, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12593.