Deihl, Steve, and Mara P. Markinson. “Connecting the Tangent Function to Cardinality: A Method for Introducing Set Theory to High School Students”. Journal of Mathematics Education at Teachers College 10, no. 2 (December 14, 2019): 1–7. Accessed April 26, 2024. https://journals.library.columbia.edu/index.php/jmetc/article/view/4190.