@article{10_14708_dm_v10i01_6864,
     author = {Aleksandra Urba\'nska},
     title = {O zjawisku konserwacji liczby u dzieci ko\'ncz\k{a}cych nauk\k{e} w {\quotedblbase}klasie zerowej{\textquotedblright}},
     journal = {Didactica Mathematicae},
     pages = { 69--98},
     publisher = {mathdoc},
     volume = {10},
     number = {01},
     year = {1989},
     doi = {10.14708/dm.v10i01.6864},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/dm.v10i01.6864/}
}