Siahaan R, Sitorus M, Silaban S. The development of teaching materials oriented to critical thinking skills for chemistry class XI high school. J.Pendidik.Kim [Internet]. 2021 Apr. 1 [cited 2025 Jul. 1];13(1):60-8. Available from: https://jurnal.unimed.ac.id/2012/index.php/jpk/article/view/24145