@article{CMUC_2010__51_3_a12,
     author = {Zapletal, Jind\v{r}ich},
     title = {On the existence of a $\sigma $-closed dense subset},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {513--517},
     publisher = {mathdoc},
     volume = {51},
     number = {3},
     year = {2010},
     mrnumber = {2741884},
     zbl = {1224.03029},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2010__51_3_a12/}
}