Badillo-Feliciano, José, and Raúl Abrams. “Performance of Eight Cowpea (Vigna Unguiculata) Cultivars on an Oxisol in Northwestern Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 65, no. 1 (January 1, 1981): 62–68. Accessed November 23, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/7564.