Purwoko, Purwoko, Muhammad Romli, Suprihatin Suprihatin, and Liesbetini Haditjaroko. “Alkaline Pretreatment of Sorghum Stalk and Co-Digestion With Sludge for Biogas Production”. International Journal of Sciences: Basic and Applied Research (IJSBAR) 24, no. 1 (July 29, 2015): 15–23. Accessed April 29, 2024. https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/4357.