RASSIAS, J. M. On the Stability of the Multi-Dimensional Euler-Lagrange Functional Equation. The Journal of the Indian Mathematical Society, [S. l.], v. 66, n. 1-4, p. 1–9, 1999. Disponível em: https://informaticsjournals.com/index.php/jims/article/view/21902. Acesso em: 3 may. 2024.