ATTAEV, A.Kh. On a characteristic problem for a loaded hyperbolic equation. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 96, n. 4, p. 15–21, 2019. DOI: 10.31489/2019m4/15-21. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/278. Acesso em: 4 sep. 2025.