Joko, T., D. A. C. Putri, and H. L. Dangiran. “Chitosan on Reducing Chemical Oxygen Demands in Laundry Waste Water”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 30, no. 1, Sept. 2016, pp. 104-11, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/6399.