Lee, Jae Ki, Susan Licwinko, and Nicole Taylor-Buckner. “Exploring Mathematical Reasoning of the Order of Operations: Rearranging the Procedural Component PEMDAS”. Journal of Mathematics Education at Teachers College 4, no. 2 (November 26, 2013). Accessed May 22, 2022. https://journals.library.columbia.edu/index.php/jmetc/article/view/633.