@article{AUCMP_1993__34_2_a7,
     author = {Holick\'y, P.},
     title = {Local and global $\sigma$-cone porosity},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {51--57},
     publisher = {mathdoc},
     volume = {34},
     number = {2},
     year = {1993},
     mrnumber = {1282966},
     zbl = {0816.46014},
     language = {en},
     url = {https://geodesic-test.mathdoc.fr/item/AUCMP_1993__34_2_a7/}
}