Ryckelynck , Philippe, and Laurent Smoch. “On the Functional Equation αu + C ⋆ (χu) = F”. North-Western European Journal of Mathematics, no. 4 (November 7, 2017): 1–20. Accessed October 18, 2024. https://nwejm.univ-lille.fr/index.php/nwejm/article/view/42.