Oklima, A. M., Sudarsono, ., Iskandar, ., & Suryaningtyas, D. T. (2015). Utilizing Coal Ash and Humic Substances as Soil Ameliorant on Reclaimed Post-Mining Land. JOURNAL OF TROPICAL SOILS, 19(3), 161–169. https://doi.org/10.5400/jts.2014.v19i3.161-169