Fajarindo, F., Suwardi, Iskandar, A. Limin, and S. K. Dewi. “Amelioration of Ultisol Acidity Using Coal Ash and Lignite-Enriched Compost”. Acta Solum, vol. 4, no. 2, Mar. 2026, pp. 94-99, doi:10.20527/actasolum.v4i2.3614.