@article{10_14708_cm_v23i1_6047,
     author = {K. Sieklucki},
     title = {An inductive proof of the non-retractibility of a cell onto its boundary},
     journal = {Commentationes Mathematicae},
     pages = { 129--131},
     year = {1983},
     volume = {23},
     number = {1},
     doi = {10.14708/cm.v23i1.6047},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v23i1.6047/}
}