Bonnet, J. A., A. R. Riera, and J. Roldán. 1956. “Correlation at Different Ages Between Nitrogen, Green- and Dry-Matter Contents of Leaves, and Yield of Sugarcane Grown in Sand Culture”. The Journal of Agriculture of the University of Puerto Rico 40 (2):101-9. https://doi.org/10.46429/jaupr.v40i2.12641.