@article{PMFA_1980_25_6_a7,
     author = {Vy\v{s}{\'\i}n, Jan},
     title = {Varia didactica},
     journal = {Pokroky matematiky, fyziky a astronomie},
     pages = {339--343},
     year = {1980},
     volume = {25},
     number = {6},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/item/PMFA_1980_25_6_a7/}
}