DŁOTKO, Tadeusz. On the solutions of certain functional-differential equations of the n-th order. Annales Mathematicae Silesianae, [S. l.], v. 5, p. 37–42, 1991. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/14279. Acesso em: 18 apr. 2025.