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