Ni Nyoman Rupiasih, et al. “PREPARATION, CHARACTERIZATION AND USED OF POLYSULFONE MEMBRANES FOR THE TREATMENT OF WATER SOLUTIONS CONTAINING HUMIC ACIDS”. Jurnal Sains Materi Indonesia, vol. 13, no. 1, Oct. 2011, pp. 54-58, doi:10.17146/jusami.2011.13.1.5400.