Nawrocki, Adam. “On Some Applications of Convolution to Linear Differential Equations With Levitan Almost Periodic Coefficients”. Topological Methods in Nonlinear Analysis 50, no. 2 (September 16, 2017): 489–512. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2017.015.