1. On log concave sequences;Beck;Discrete Math.,1991
2. Comments on Chebycheff's inequality;Burkill;Periodica Math. Hungar.,1975
3. Inequalities;Hardy,1964
4. Analytic Inequalities;Mitrinović,1970
5. On some inequalities for convex sequences;Pečarić;Publ. Inst. Math. (Beograd),1983