@article{10_4064_cm_1_4_273_278,
     author = {Casimir Kuratowski},
     title = {Une m\'ethode de prolongement des ensembles relativement ferm\'es ou ouverts},
     journal = {Colloquium Mathematicum},
     pages = {273--278},
     publisher = {mathdoc},
     volume = {1},
     number = {4},
     year = {1947},
     doi = {10.4064/cm-1-4-273-278},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-1-4-273-278/}
}