Turmetov, B.Kh., and Mуrzakhasova A.M. “On Solvability of Fractional Analogues of the Neumann Problem for Biharmonic Equation”. Bulletin of the Karaganda University. Mathematics Series 79, no. 3 (September 29, 2015): 87–95. Accessed September 7, 2025. http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/53.