Bakhyt, S., B. Kalimbetov, and Z. Khabibullayev. “Possibilities of Mathematical Problems in Logical Thinking. Development of Secondary Education Pupils”. Opción, Vol. 34, no. 85-2, June 2019, pp. 441-57, https://mail.produccioncientificaluz.org/index.php/opcion/article/view/23803.