Sittijunda, S. “Biogas production from hydrolysate napier grass by co-digestion with slaughterhouse wastewater using anaerobic mixed cultures”. Asia-Pacific Journal of Science and Technology, vol. 20, no. 3, Nov. 2015, pp. 323-36, https://so01.tci-thaijo.org/index.php/APST/article/view/42637.