Use of Unmodified Coffee Husk Biochar and Ashes as Heterogeneous Catalysts in Biodiesel Synthesis - Joycel V. Fernández; Diêgo N. Faria; Mariana C. Santoro; Rafael Mantovaneli; Daniel F. Cipriano; Gilberto M. Brito; Maria Tereza W. D. Carneiro; Miguel A. Schettino; Jorge L. Gonzalez; Jair C. C. Freitas (BioEnergy Research, 2023)