Aisagaliev S. А., and S. S. Aisagalieva. “Construction of a Solution of the Controllability Problem for Linear Integral and Differential Equations With Restrictions”. Journal of Mathematics, Mechanics and Computer Science, vol. 94, no. 2, July 2018, pp. 3-22, https://bm.kaznu.kz/index.php/kaznu/article/view/442.