Asenjo, C. F., and M. del C. C. de Fernández. “USES, PREPARATION, AND PROPERTIES OF PINGUINAIN, THE PROTEIN-SPLITTING ENZYME OF THE MAYA FRUIT”. The Journal of Agriculture of the University of Puerto Rico 29, no. 2 (April 1, 1945): 35–46. Accessed April 20, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12871.