Apakov, Yu. P. “Boundary-Value Problem for a Degenerate High-Odd-Order Equation”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 10 (October 25, 2014): 1318–1331. Accessed April 18, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2224.