Roa-Neri, J., M. Villavicencio, ., and J. Jiménez. “On the Radiation by a Charge in a Material Medium”. Revista Mexicana De Física, vol. 39, no. 2, Jan. 1992, pp. 314-28, https://rmf.smf.mx/ojs/index.php/rmf/article/view/2326.