@article{UM_2014__22_4_a4, author = {Vlk, V\'aclav}, title = {Jak to vlastn\v{e} je?}, journal = {U\v{c}itel matematiky}, pages = {243--252}, publisher = {mathdoc}, volume = {22}, number = {4}, year = {2014}, language = {cz}, url = {http://geodesic.mathdoc.fr/item/UM_2014__22_4_a4/} }