Ulfa, Nadia, Al Jupri, Darhim, and Kartika. “Analysis of Learning Obstacles of Junior High School Students on The Topic of Circle”. Proceeding International Conference on Science and Engineering 3 (April 30, 2020): 599–603. Accessed September 13, 2026. http://sunankalijaga.org/prosiding/index.php/icse/article/view/572.