1. Problem 5642;Redheffer;Amer. Math. Monthly,1969
2. Three inequalities involving hyperbolically trigonometric functions;Chen;RGMIA Res. Rep. Coll.,2003
3. Redheffer type inequality for Bessel functions;Baricz;J. Inequal Pure Appl. Math.,2007
4. Handbook of Means and their Inequalities;Bullen,2003
5. From Fermat to Minkowski;Scharlau,1985