H. Avci and E. Tunç, “Solvability of inhomogeneous boundary-value problems for fourth-order differential equations”, Ukr. Mat. Zhurn., vol. 63, no. 9, pp. 1263–1278, Sep. 2011, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2803