Lestari R, Sukmawardani Y, Subarkah CZ, Farida I. Application of Problem-Based Worksheets to Develop Higher Order Thinking Skills In The Utilization of Coconut Shells As Zn Metal Adsorbent In Laboratory Waste. HJKK [Internet]. 2024 Aug. 30 [cited 2025 Aug. 16];12(4):879-92. Available from: https://e-journal3.undikma.ac.id/index.php/hydrogen/article/view/12191