Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Santosa Sri Juari and Sudiono Sri and Sujandi Sri,Peat Soil Humic Acid Immobilization on Silica Gel and Its Application as an Adsorbent for the Selective Adsorption of Copper,e-Journal of Surface Science and Nanotechnology,1348-0391,The Japan Society of Vacuum and Surface Science,2006,4,,602-608,https://cir.nii.ac.jp/crid/1390282680161722240,https://doi.org/10.1380/ejssnt.2006.602