Kalybay, A., and S. Shalginbayeva. “Estimate of the Best Constant of Discrete Hardy-Type Inequality With Matrix Operator Satisfying the Oinarov Condition”. Eurasian Mathematical Journal, vol. 15, no. 2, July 2024, pp. 42-47, https://emj.enu.kz/index.php/main/article/view/341.