Alvarado, M., Jesús Fernando Novoa Ramírez, and L. Rodríguez. “UNA NOTA SOBRE EL ESPACIO NULA”. Universitas Scientiarum 8 (July 10, 2003): 7–12. Accessed July 17, 2024. https://revistas.javeriana.edu.co/index.php/scientarium/article/view/4850.