Fajar, Mutiara, et al. “STUDY ON THE EFFECTIVENESS OF ACTIVATED CARBON FOR REDUCING HARDNESS AND IRON (FE) CONTENT IN WELL WATER”. Lingkar: Journal of Environmental Engineering, vol. 5, no. 1, June 2023, pp. 1-9, https://journal.ar-raniry.ac.id/index.php/lingkar/article/view/6006.