labanu, ratna s, Iqbal Iqbal, and dedy farhamsa. “Mapping Projections Of Water Hardness Of The Groundwater In Palu Using The Web-Based Google MapsAPI”. Gravitasi 14, no. 1 (June 30, 2015). Accessed November 22, 2024. https://bestjournal.untad.ac.id/index.php/GravitasiFisika/article/view/4437.