Kungozhin, A. M. (2011) “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, 69(2), pp. 39–43. Available at: https://bm.kaznu.kz/index.php/kaznu/article/view/193 (Accessed: 22 December 2024).