@article{ELMA_1950__5_140526,
     author = {W. Sierpinski},
     title = {Sur quelques probl\`emes concernant la congruence des ensembles de points.},
     journal = {Elemente der Mathematik},
     pages = {1--4},
     publisher = {mathdoc},
     volume = {5},
     year = {1950},
     zbl = {0035.15202},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1950__5_140526/}
}