Kulwarang Suwanasri. (1999) Removal efficiency of humic acid in raw water by using potassium permanganate and alum in coagulation. Mahidol University,:ม.ป.ท.Kulwarang Suwanasri. 1999. Removal efficiency of humic acid in raw water by using potassium permanganate and alum in coagulation. ม.ป.ท.:Mahidol University,;Kulwarang Suwanasri. Removal efficiency of humic acid in raw water by using potassium permanganate and alum in coagulation. ม.ป.ท.:Mahidol University, 1999. Print.