The generalized Hyers-Ulam-Rassias stability of a quadratic functional equation. Ravi, K.; Murali, R.; Arunkumar, M. — 2008 JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]
Stability of a generalized mixed type additive, quadratic, cubic and quartic functional equation. Ravi, K.; Rassias, John Michael; Arunkumar, M.; Kodandan, R. — 2009 JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]