Guadarrama-Santana, A., and A. García-Valenzuela. “Non-Destructive Measurement of the Dielectric Constant of Solid Samples”. Revista Mexicana De Física, vol. 55, no. 6, Jan. 2009, pp. 477-0, https://rmf.smf.mx/ojs/index.php/rmf/article/view/3719.