@article{UM_1998_6_4_a0,
     author = {Ku\v{r}ina, Franti\v{s}ek},
     title = {Matematika v obrazech (4)},
     journal = {U\v{c}itel matematiky},
     pages = {193--202},
     year = {1998},
     volume = {6},
     number = {4},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/item/UM_1998_6_4_a0/}
}