Utami, Nanik. “Improving the Students’ Comprehension on Acid Natural Indicator through Discovery Learning”. Tamansiswa International Journal in Education and Science (TIJES) 3, no. 2 (April 30, 2022): 63–73. Accessed December 9, 2022. https://jurnal.ustjogja.ac.id/index.php/TIJES/article/view/12250.