YESHKEYEV, A.R.; OMAROVA, M.T. Central types of convex fragments of the perfect Jonsson theory. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 93, n. 1, p. 95–101, 2019. DOI: 10.31489/2019m1/95-101. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/288. Acesso em: 7 sep. 2025.