Wichianphong, N., and W. Maison. “Preparation of Biofuel Pellets from Water Hyacinth and Waste Coffee Grounds”. RMUTSB ACADEMIC JOURNAL, vol. 8, no. 2, Dec. 2020, pp. 140-52, https://li01.tci-thaijo.org/index.php/rmutsb-sci/article/view/247484.