@misc{Tlaskal_Jakub_Knowledge_2011,
 author={Tlaskal, Jakub and Benesova, Ludmila and Slezakova, Jana and Molnar, Josef},
 type={artykuł},
 publisher={Wydawnictwo Akademii im. Jana Długosza w Częstochowie},
 title={Knowledge of quadrilateral at elementary school},
 address={Częstochowa},
 year={2011},
 language={eng},
}