Anh, N. V., V. T. M. Thanh, B. T. Thuy, N. T. Hue, and T. H. Nhue. “MASS BALANCE AND ENERGY ANALYSIS OF A WASTEWATER SLUDGE ANAEROBIC DIGESTION SYSTEM FOR ENERGY RECOVERY”. Journal of Science and Technology in Civil Engineering (JSTCE) - HUCE, vol. 10, no. 5, Oct. 2016, pp. 122-6, https://stce.vjst.net/index.php/en/article/view/304.