Suryani, Yani. “Optimizing the Volume of Starter and the Time of Fermentation in the Production of Biogas from Vegetable Wastes With Maximum Content of Methane Gas”. Journal of Asian Scientific Research 2, no. 12 (December 3, 2012): 789–797. Accessed May 15, 2024. https://archive.aessweb.com/index.php/5003/article/view/3429.