Castro Grijalba, Alexánder, et al. “Preparation and Characterization of Cassiterite (Sno2) and Its Application in the Hydrogenation of Methyl Esters”. Revista De Ciencias, vol. 17, no. 3, Dec. 2013, pp. 81-93, https://doi.org/10.25100/rc.v17i3.481.