Yeshkeyev, A. and Ulbrikht, O. (2015) “On lattice of existential formulas for fragment of Jonsson set”, Bulletin of the Karaganda University. Mathematics Series, 3(79), pp. 33–39. Available at: https://mts.buketov.edu.kz/mathematics-vestnik/article/view/44 (Accessed: 8 December 2025).