@misc{Gradziński_Ryszard_Powstanie_1951,
 author={Gradziński, Ryszard},
 volume={7},
 number={1/2},
 copyright={Creative Commons Attribution BY 3.0 PL license},
 address={Kraków},
 journal={Let's protect Our Indigenous Nature},
 howpublished={online},
 year={1951},
 publisher={Commitee of Nature Protection of the Polish Academy of Learning},
 language={pol},
 title={Powstanie i rozwój jaskiń},
 type={Text},
 URL={http://www.rcin.org.pl/Content/233866/KR038_248152_r1951-t7-no1-2_ChPO-Gradzinski-11-19.pdf},
}