... Institute of Mathematics, Seoul National University.Author details1Department of Mathematics, Hanyang University, Seoul 133-791, Republic of Korea2Department of Mathematics,University of Ulsan, ... Ulsan 680-749, Republic of Korea3Department of Mathematics, Daejin University, Kyeonggi 487-711, Republic of Korea4Department of Mathematics, University of Seoul, Seoul 130-743, Republic of ... of quartic and quadratic functional equation.Park et al. Journal of Inequalities and Applications 2011, 2011:34http://www.journalofinequalitiesandapplications.com/content/2011/1/34Page 2 of...