Medina Gaud, Silverio. “Preliminary Study on the Control of the Cottony-Cushion Scale (Icerya Purchasii Maskell,) by Means of Insecticides”. The Journal of Agriculture of the University of Puerto Rico 43, no. 4 (October 1, 1959): 295–299. Accessed December 22, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12573.