Ramírez-Corzo, José, and Luis Mendoza. “Dual Silent Communication System Development Based on Subvocal Speech and Raspberry Pi”. Revista Facultad de Ingeniería 25, no. 43 (September 1, 2016): 111-121. Accessed November 30, 2020. https://revistas.uptc.edu.co/index.php/ingenieria/article/view/5304.