Belaïdi , Benharrat, and Yamina Lassal. “Complex Linear Differential Equations With Analytic Coefficients of Iterated Order in the Annulus”. Jordan Journal of Mathematics and Statistics 15, no. 3 (January 14, 2023): 417–434. Accessed November 21, 2024. https://jjms.yu.edu.jo/index.php/jjms/article/view/5.