Strict Proof of the Perfection of the First 98 Masks (Solution to the X-Problem of the Number 3). Global Journal of Science Frontier Research, [S. l.], v. 17, n. A4, p. 43–56, 2017. Disponível em: https://www.journalofscience.org/index.php/GJSFR/article/view/102317. Acesso em: 13 aug. 2026.