“PURIFICATION EXPERIMENTS ON THE PASIG RIVER, PHILIPPINES USING A CIRCULATION-TYPE PURIFICATION SYSTEM”, INTERNATIONAL JOURNAL OF GEOMATE, vol. 16, no. 54, pp. 49–54, Feb. 2021, Accessed: Apr. 18, 2026. [Online]. Available: https://geomatejournal.com/geomate/article/view/2624