John M. Rassias, M. Arunkumar, E. Sathya, and N. Mahesh Kumar. “Generalized Ulam - Hyers Stability of on (AQQ): Additive-Quadratic-Quartic Functional Equation”. Malaya Journal of Matematik 5, no. 01 (January 1, 2017): 122–142. Accessed November 24, 2024. https://www.malayajournal.org/index.php/mjm/article/view/585.