Akkaoui, A., El Fatini, M. and Fadli, B. (2022) “A variant of d’Alembert’s functional equation on semigroups with endomorphisms”, Annales Mathematicae Silesianae, 36(1), pp. 1–14. Available at: https://journals.us.edu.pl/index.php/AMSIL/article/view/13456 (Accessed: 5 December 2025).