@article{UM_2009_17_3_a1,
     author = {Sm\'ykalov\'a, Radka},
     title = {St\v{r}edov\v{e}k\'y zrod trigonometrick\'ych veli\v{c}in},
     journal = {U\v{c}itel matematiky},
     pages = {143--157},
     year = {2009},
     volume = {17},
     number = {3},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/item/UM_2009_17_3_a1/}
}