Rina Febrina, and Abu Bakar Sambah. “WATER QUALITY ASSESMENT BASED ON THE WATER QUALITY INDEX (WQI) APPROACH USING GEOSPATIAL ANALYSIS”. GEOMATE Journal, vol. 16, no. 56, Apr. 2019, pp. 135-40, https://geomatejournal.com/geomate/article/view/2685.