References
- [PSV] PAŠTÉKA, M.-ŠALÁT, T.-VISNYAI, T.: Remarks on Buck’s measure density and a generalization of asymptotic density, Tatra Mt. Math. Publ. 31 (2005), 87-101.
- [OB] OBATA, N.: Density of natural numbers and the Levy group, J. Number Theory 30 (1988), 288-297. 10.1016/0022-314X(88)90003-0
- [NP] NATHANSON, M. B.-PARIKH, R.: Density of sets of natural numbers and the Levy group, J. Number Theory 124 (2007), 151-157. 10.1016/j.jnt.2006.09.001
- [LEV] LEVY, P.: Problemes concrets d’Analyse Fonctionelle, Gauthier Villars, Paris, 1951.