Almahalebi, M., A. Charifi, and S. Kabbaj. “HYPERSTABILITY OF A CAUCHY FUNCTIONAL EQUATION”. Journal of Nonlinear Analysis and Optimization: Theory & Applications (JNAO), vol. 6, no. 2, Nov. 2016, pp. 127-3, https://ph03.tci-thaijo.org/index.php/jnao/article/view/2786.