References
- G. H. Hardy, J. E. Littlewood, G. Polya, Inequalities, Cambridge, 1975.
-
J. Karamata, Sur l'approximation de
$e^{x}$ par des fonctions rationnelles (in Serbian), Bull. Soc. Math. Phys. Serbie, 1 (1949), 7-19. - S.-H. Kim, Densely algebraic bounds for the exponential function, Proc. Amer. Math. Soc. 135 (2007), 237-241. https://doi.org/10.1090/S0002-9939-06-08452-8
- W. E. Sewell, Some inequalities connected with exponential function (in Spanish) Rev. Ci (Lima), 40 (1938), 453-456.
-
J. E. Wetzel, On the functional inequality f(x + y)
${\ge}$ f(x) f(y), Amer. Math. Monthly 74 (1967), 1065-1068. https://doi.org/10.2307/2313604