@article{COMIM_2007__15_1_a2,
     author = {Kijonka, V\'aclav},
     title = {On relations between $f$-density and $(R)$-density},
     journal = {Communications in Mathematics},
     pages = {15--20},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {2007},
     mrnumber = {2418778},
     zbl = {1235.11016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/COMIM_2007__15_1_a2/}
}