Wei, Gao, Lope G Tabil, Zhao Rongfei, and Liu Qingyu. 2016. “Optimized Design and Experiment on Ring Mold Pelletizer for Producing Biomass Fuel Pellets”. International Journal of Agricultural and Biological Engineering 9 (3):57-66. https://www.ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/2074.