Team, S. “A Mixed-Type Quadratic and Cubic Functional Equation and Its Stability: Wanchitra Towanlong, Paisan Nakmahachalasint”. Thai Journal of Mathematics, vol. 8, no. 4, Dec. 2010, pp. 61-71, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/236.