Hogue, Mark D., Miranda Spengler, Rachel Hughes, and Caitlyn Bell. “Building a Foundational Understanding of Systems of Equations”. Ohio Journal of School Mathematics 94, no. 1 (August 2, 2023): 21–30. Accessed September 27, 2023. https://ohiomathjournal.org/index.php/OJSM/article/view/9482.