Kurina, G.A., and M.A. Kalashnikova. “Minimizing Sequences for a Linear-Quadratic Control Problem With Three-Tempo Variables under Weak Nonlinear Perturbations”. Bulletin of the Karaganda University. Mathematics Series 109, no. 1 (March 30, 2023): 94–109. Accessed August 27, 2025. http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/555.