Perez, Y, A Gonzalez, J Castillo, A Sanchez, P Oliveira, and C Pichara. 2019. “Obtaining and Characterization of Pellets Based on Walnut Shells, Waste Paper and Paperboard”. Revista Técnica De La Facultad De Ingeniería. Universidad Del Zulia 42 (3), 181-86. https://produccioncientificaluz.org/index.php/tecnica/article/view/30217.