@article{ARM_1976__12_1_a6,
     author = {Chvalina, Jan},
     title = {Concerning a non-realizability of connected compact semi-separated closure operations by set-systems},
     journal = {Archivum mathematicum},
     pages = {45--51},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1976},
     mrnumber = {0438266},
     zbl = {0356.54003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ARM_1976__12_1_a6/}
}