Jiménez-Domínguez, H., H. Flores-Llamas, A. Cabral-Prieto, F. Ramírez-Jiménez, and and S. Galindo. “Capacitive Axial Position and Speed Transduction System”. Revista Mexicana De Física, vol. 30, no. 2, Jan. 1983, pp. 289-9, https://rmf.smf.mx/ojs/index.php/rmf/article/view/1275.