Razi, Faizal, Heru Hendrayana, and Agung Harijoko. “Identification and Distribution of Fluoride in Singkep Island, Lingga Regency, Riau Islands”. Journal of Degraded and Mining Lands Management 11, no. 4 (July 1, 2024): 6185–6199. Accessed April 25, 2025. https://jdmlm.ub.ac.id/index.php/jdmlm/article/view/16555.