Wolcott, George N. “Dispersion to the Tropics of the Spiraea Aphid, Aphis Spiraecola Patch”. The Journal of Agriculture of the University of Puerto Rico 39, no. 1 (January 1, 1955): 32–40. Accessed April 25, 2024. https://revistas.upr.edu/index.php/jaupr/article/view/12696.