Jumiati, Ety, Nazaruddin Nasution, & Dika Prananda. " Reducing Mn Levels from Bore Well Water in Tembung Village by Filtration of Tea Bag Activated Carbon, Zeolite, Silica Sand and Gravel." BULETIN FISIKA [Online], 24.2 (2023): 149 – 153. Web. 4 May. 2024