Ryckelynck P, Smoch L. On the functional equation αu + C ⋆ (χu) = f. NWEJM [Internet]. 2017 Nov. 7 [cited 2025 Feb. 16];(4):1-20. Available from: https://nwejm.univ-lille.fr/index.php/nwejm/article/view/42