BEKENOV, M.I.; MAMYRALY, A.; KASSATOVA, A.; KABIDENOV, A. Criterion for a formula-definable quasivariety. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 121, n. 1, p. 103–109, 2026. DOI: 10.31489/2026m1/103-109. Disponível em: https://mts.buketov.edu.kz/mathematics-vestnik/article/view/1210. Acesso em: 4 apr. 2026.