Schubert, Thomas H., and José A. Zambrana. “Araucaria Heterophylla and Pinus Caribaea: Potential Christmas Trees for Puerto Rico”. The Journal of Agriculture of the University of Puerto Rico 66, no. 2 (April 1, 1982): 145–149. Accessed April 23, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/7658.