Pitriani, ., M. Fajaruddin Natsir, and A. Daud. “The Effectiveness of EM4 Addition into Anaerob-Aerob Biofilter in the Processing of Wastewater at Hasanuddin University Hospital, Makassar Indonesia”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 22, no. 1, Apr. 2015, pp. 178-87, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/3845.