Darwin, Darwin, Jay J. Cheng, Zhimin Liu, Jorge Gontupil, and O-Seob Kwon. 2014. “Anaerobic Co-Digestion of Rice Straw and Digested Swine Manure With Different Total Solid Concentration for Methane Production”. International Journal of Agricultural and Biological Engineering 7 (6):79-90. https://ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/1199.