Nugrahani, Maria Bestanika, and Risnita Vicky Listyarini. “Development of Universal Indicator from Organic Waste Material”. Jurnal Penelitian Pendidikan IPA 9, no. 4 (April 30, 2023): 1765–1771. Accessed May 20, 2024. https://jppipa.unram.ac.id/index.php/jppipa/article/view/1567.