@misc{PMFA_1967_12_6_a15,
     title = {\'Ulohy pro fyzik\'aln{\'\i} olympi\'adu},
     journal = {Pokroky matematiky, fyziky a astronomie},
     pages = {388},
     year = {1967},
     volume = {12},
     number = {6},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/item/PMFA_1967_12_6_a15/}
}