M. Arunkumar, M. J. Rassias, S. Hema Latha, and Yanhui Zhang. 2015. “Ulam Stabilities of $K$ - AC - Mixed Type Functional Equations in Three Variables”. International Journal of Mathematics And Its Applications 3 (4 - C):49-78. http://ijmaa.in/index.php/ijmaa/article/view/507.