1. Abramovich S., Banić S., Matić M.: Superquadratic functions in several variables. J. Math. Anal. Appl. 137(2), 1444–1460 (2007)
2. Abramovich S., Jameson G., Sinnamon G.: Refining of Jensen’s inequality. Bull. Math. Soc. Sci. Math. Roumanie (N.S.) 47(95), 3–14 (2004)
3. Abramovich, S., Jameson, G., Sinnamon, G.: Inequalities for averages of convex and superquadratic functions. J. Inequal. Pure Appl. Math. 7(2) (2004), Art. 70. http://jipam.vu.edu.au/
4. Carleman, T.: Sur les fonctions quasi-analytiques. Comptes rendus du Ve Congres des Mathematiciens Scandinaves, Helsingfors 1922, pp. 181–196
5. Godunova, E.K.: Inequalities based on convex functions. Izv. Vysh. Uchebn. Zaved. Matematika 47(4), 45–53 (1965) (English transl. in Am. Math. Soc., Transl., II Ser 88, 57–66 (1970))