ZHOLDYBEKOV, E.T. On solutions of some mathematical problems. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 80, n. 4, p. 74–81, 2015. Disponível em: https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/63. Acesso em: 10 jul. 2025.