“A STUDY ON CLAY SOIL IMPROVEMENT WITH BACILLUS SUBTILIS BACTERIA AS THE ROAD SUBBASE LAYER”, INTERNATIONAL JOURNAL OF GEOMATE, vol. 15, no. 52, pp. 114–120, Sep. 2018, Accessed: Aug. 21, 2026. [Online]. Available: https://geomatejournal.com/geomate/article/view/797