@misc{Demirci_Necip_Step_2021,
 author={Demirci, Necip and Yilmaz, Refika and Karaca, Ayda},
 type={artykuł},
 publisher={Projack},
 title={Step count for 7th and 8th grade students in structured and unstructured physical education classes},
 address={Częstochowa},
 year={2021},
 language={eng},
}