@article{WM_1897_1_1_a7,
     author = {Niew\k{e}g{\l}owski, B.},
     title = {Zagadnienia},
     journal = {Wiadomo\'sci Matematyczne},
     pages = {51--52},
     publisher = {mathdoc},
     volume = {1},
     number = {1},
     year = {1897},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/item/WM_1897_1_1_a7/}
}