Bhavin Mansukhlal Patel. (2026). On the Stability of the Quadratic Functional Equation $f(2x+y) + f(x+2y)$ $= 4f(x+y) + f(x) + f(y)$ in $2$-Banach Space. International Journal of Mathematics And Its Applications, 13(4), 41–53. Retrieved from https://ijmaa.in/index.php/ijmaa/article/view/1631