1. Aczél, J., Dhombres, J.: Functional Equations in Several Variables. With Applications to Mathematics, Information Theory and to the Natural and Social Sciences. Encyclopedia of Mathematics and its Applications, vol. 31. Cambridge University Press, Cambridge (1989)
2. Alsina, C., García Roig, J.L.: On some inequalities characterizing the exponential function, Arch. Math. Brno 26(2–3), 67–71 (1990)
3. Alsina, C., Ger, R.: On some inequalities and stability results related to the exponential function. J. Inequal. Appl. 2(4), 373–380 (1998)
4. Burk, F.: Notes: The geometric, logarithmic, and arithmetic mean inequality. Amer. Math. Mon. 94(6), 527–528 (1987)
5. Carlson, B.C.: The logarithmic mean. Amer. Math. Mon. 79, 615–618 (1972)