YESHKEYEV, A.R.; MUSSINA, N.M. An algebra of the central types of the mutually model-consistent fragments. Bulletin of the Karaganda University. Mathematics Series, [S. l.], v. 101, n. 1, p. 111–118, 2021. DOI: 10.31489/2021m1/111-118. Disponível em: http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/434. Acesso em: 10 jul. 2025.