KUNGOZHIN, A. M. Description of positively existentially closed models in any class of -structures with unary predicates axiomatizable by any h-universal sentence. Journal of Mathematics, Mechanics and Computer Science, [S. l.], v. 69, n. 2, p. 39–43, 2011. Disponível em: https://bm.kaznu.kz/index.php/kaznu/article/view/193. Acesso em: 22 dec. 2024.