E. Novita, H. A. Pradana, S. Wahyuningsih, B. Mahraenanto, M. W. sujarwo, and M. salman A. Hafidz, “ANAEROBIC DIGESTER VARIATION FOR BIOGAS PRODUCTION ON COFFEE WASTEWATER TREATMENT”, JTEP-L, vol. 8, no. 3, pp. 164–174, Sep. 2019.