Rodríguez, Saulo J., and Carlos Rivera-López. “Effect of Six Levels of N on the Growth of Sanders Dracaena (Dracaena Sanderiana, Hort.) at a 47 Percent Shade”. The Journal of Agriculture of the University of Puerto Rico, vol. 61, no. 3, July 1977, pp. 314-8, doi:10.46429/jaupr.v61i3.10429.