@misc{Eberhardt_Piotr_(1935–2020)_Koncepcja_2011,
 author={Eberhardt, Piotr (1935–2020)},
 volume={83},
 number={2},
 copyright={Rights Reserved - Free Access},
 address={Warszawa},
 journal={Przegląd Geograficzny},
 howpublished={online},
 year={2011},
 publisher={IGiPZ PAN},
 language={pol},
 language={eng},
 language={pol},
 type={Text},
 title={Koncepcja Heartlandu Halforda Mackindera = Halford Mackinder's Heartland concept},
 URL={http://www.rcin.org.pl/igipz/Content/1849/PDF/Wa51_12800_r2011-t83-z2_Przeg-Geogr-Eberhardt.pdf},
}