Adamchik , V. S., and A. D. Lizarev. “Wronskians of Solutions for One Class of Differential Equations With Polynomial Coefficients”. Ukrains’kyi Matematychnyi Zhurnal 40, no. 6 (November 1, 1988): 694–699. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/9276.