Rubio and H, J. “On the Effect of X-Irradiation on Impurity Vacancy Dipoles and the Influence of Their Aggregation-Precipitation State in the Room Temperature Coloring of the Alkali Halides”. Revista Mexicana De Física, vol. 30, no. 1, Jan. 1983, pp. 1-39, https://rmf.smf.mx/ojs/index.php/rmf/article/view/1261.