Cruz, Luis M., Justo López, and Frank J. Juliá. “Cabbage Hybrid Performances Under Different Planting Methods”. The Journal of Agriculture of the University of Puerto Rico 60, no. 1 (January 1, 1976): 22–30. Accessed December 23, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/10582.