1.
Karolina R, Sofran MA, Handana M, Syahrizal, Siregar RI. Geopolymer Concrete Made From Volcanic Ash of Mount Sinabung. IJIE. 2020;12(1):315-320. Accessed March 12, 2026. https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/5732