SIDDIQ MAHMOUD, A.; IBRAHIM BAKR, R. The hybrid Morse code. Journal of Education and Science (JES), [S. l.], v. 28, n. 1, p. 294–311, 2019. DOI: 10.33899/edusj.2019.161056. Disponível em: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/23452. Acesso em: 6 aug. 2025.