Rangel Rojo, R., E. Haro Poniatowsk, ., and A. Muñoz Flores. “Nonresonant Third-Order Optical Nonlinearity of Amorphous Selenium With Picosecond Pulses”. Revista Mexicana De Física, vol. 43, no. 6, Jan. 1996, pp. 960-5, https://rmf.smf.mx/ojs/index.php/rmf/article/view/2719.