HIDALGO, R. A. The structure of extended function groups. CUBO, A Mathematical Journal, [S. l.], v. 23, n. 3, p. 369–384, 2021. DOI: 10.4067/S0719-06462021000300369. Disponível em: https://www.perspectivasdelacomunicacion.cl/ojs/index.php/cubo/article/view/2849. Acesso em: 18 may. 2024.