C. A. Valerio Lizarraga, C. Duarte-Galvan, I. Leon-Monzon, P. Villaseñor, and and J. Aspiazu, “A Study on the negative ion beam production in the ININ sputtering ion source”, Rev. Mex. Fís., vol. 65, no. 3 May-Jun, pp. 278–283, May 2019.