YOUNIS, S.; SALIH, O. The effects of the vision on the central opacity and the positions of the curves invers for the brightness of the assumed elliptic sphere. Journal of Education and Science, [S. l.], v. 18, n. 1, p. 79–96, 2006. DOI: 10.33899/edusj.2006.78665. Disponível em: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/41553. Acesso em: 7 sep. 2025.