Setiawati, D. ., Y. Diksy, and A. P. . Tirta. “Performance Test for COD Determination in Wastewater Using a Closed Reflux Method With a COD Reactor”. Indonesian Journal of Applied Environmental Studies, vol. 6, no. `1, Apr. 2025, pp. 20-25, doi:10.33751/injast.v6i`1.5.