“HEATING VALUE ENHANCEMENT BY BIOGAS PURIFICATION USING NATURAL ZEOLITE AND RICE STRAW-BASED BIOCHAR”, INTERNATIONAL JOURNAL OF GEOMATE, vol. 16, no. 55, pp. 80–85, Mar. 2019, Accessed: May 10, 2026. [Online]. Available: https://geomatejournal.com/geomate/article/view/2483