Lestari, Risma, Yulia Sukmawardani, Cucu Zaenab Subarkah, and Ida Farida. “Application of Problem-Based Worksheets to Develop Higher Order Thinking Skills In The Utilization of Coconut Shells As Zn Metal Adsorbent In Laboratory Waste”. Hydrogen: Jurnal Kependidikan Kimia 12, no. 4 (August 30, 2024): 879–892. Accessed August 16, 2025. https://e-journal3.undikma.ac.id/index.php/hydrogen/article/view/12191.