Turmetov, B. K., and A. E. Bekayeva. “About Operator Method of Solution of Some Boundary Value Problems for Inhomogeneous Biharmonic Equation”. Journal of Mathematics, Mechanics and Computer Science, vol. 71, no. 4, Dec. 2011, pp. 62-71, https://bm.kaznu.kz/index.php/kaznu/article/view/222.