@misc{Natanson_Władysław_(1864–1937)_Widnokrąg_1934,
 author={Natanson, Władysław (1864–1937)},
 copyright={Public Domain},
 address={Lwów},
 howpublished={online},
 year={1934},
 publisher={Książnica-Atlas},
 language={pol},
 title={Widnokrąg nauki},
 URL={http://rcin.org.pl/Content/2870/PDF/WA488_5533_11828_Natanson-Widnokrag.pdf},
 keywords={Science - popular publications},
}