@article{CMUC_2004_45_1_a3,
     author = {Zelen\'y, Miroslav and Pelant, Jan},
     title = {The structure of the $\sigma$-ideal of $\sigma$-porous sets},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {37--72},
     year = {2004},
     volume = {45},
     number = {1},
     mrnumber = {2076859},
     zbl = {1101.28001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2004_45_1_a3/}
}