Prasetyo, E., & Toyoda, K. (2017). Solid Phase Extraction of Thorium and Uranium and their Separation from Lanthanides using Humic Acid Silica Gel as a Low-Cost Adsorbent. Journal of Engineering and Technological Sciences, 49(4), 508-519. https://doi.org/10.5614/j.eng.technol.sci.2017.49.4.6