INDONESIAN PEAT SOIL DERIVED HUMIC ACID ITS CHARACTERIZATION, IMMOBILIZATION, AND PERFORMANCE AS METAL SORBENT - , Sri Juari Santosa, Shigeru Tanaka, Dwi Siswanta, Eko Sri Kunarti ([Yogyakarta] : Fak. MIPA Universitas Gadjah Mada, 2007)