Kostelnick, John C., J. Devin Land, and James F. Juola. “Judgments of Size Change Trends in Static and Animated Graduated Circle Displays”. Cartographic Perspectives, no. 57 (June 1, 2007): 41–55. Accessed April 27, 2024. https://cartographicperspectives.org/index.php/journal/article/view/cp57-kostelnick-et-al.