@article{AUPCDM_2010_3_1_a4,
     author = {G\'orowski, Jan and {\L}omnicki, Adam},
     title = {O \'srednich},
     journal = {Annales Universitatis Paedagogicae Cracoviensis. Studia ad Didacticam Mathematicae Pertinentia},
     pages = {56--66},
     year = {2010},
     volume = {3},
     number = {1},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/item/AUPCDM_2010_3_1_a4/}
}