@article{10_14708_cm_v29i2_6279,
     author = {S. Siudut},
     title = {Generalizations of {Natanson{\textquoteright}s} lemma},
     journal = {Commentationes Mathematicae},
     pages = { 277--286},
     year = {1990},
     volume = {29},
     number = {2},
     doi = {10.14708/cm.v29i2.6279},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v29i2.6279/}
}