Purwoko, P., Romli, M., Suprihatin, S., & Haditjaroko, L. (2015). Alkaline Pretreatment of Sorghum Stalk and Co-Digestion with Sludge for Biogas Production. International Journal of Sciences: Basic and Applied Research (IJSBAR), 24(1), 15–23. Retrieved from https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/4357