Dzhumabaev, D. S., and K. I. Usmanov. “On the Way to Investigation of Linear Boundary Value Problem for Systems of Integral Differential Equations With Loading”. Journal of Mathematics, Mechanics and Computer Science, vol. 65, no. 2, June 2010, pp. 42-47, https://bm.kaznu.kz/index.php/kaznu/article/view/232.