“Penentuan Kondisi Kualitas Perairan Muara Sungai Somber, Balikpapan, Kalimantan Timur dengan Metode Indeks Pencemaran (Pollution Index)”. SPECTA Journal of Technology, vol. 4, no. 2, Juni 2020, hlm. 23-34, https://doi.org/10.35718/specta.v4i2.186.