Flores-Camacho, J., O. Núñez-Olvera, G. Rodríguez-Pedroza, A. Lastras Martínez, and L. Lastras-Martínez. “Lock-in Amplifier-Based Rotating-Analyzer Spectroscopic Ellipsometer With Micro-Controlled Angular Frequency”. Revista Mexicana De Física, vol. 51, no. 3, Jan. 2005, pp. 274-0, https://rmf.smf.mx/ojs/index.php/rmf/article/view/3370.