PARASIDIS, I.N.; PROVIDAS, E. Factorization of abstract operators into two second degree operators and its applications to integro-differential equations. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 113, n. 1, p. 149–161, 2024. DOI: 10.31489/2024m1/149-161. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/692. Acesso em: 4 sep. 2025.