@misc{Cassirer_Ernst_(1874–1945)_Zur_1921,
 author={Cassirer, Ernst (1874–1945)},
 copyright={Public Domain},
 address={Berlin},
 howpublished={online},
 year={1921},
 publisher={Bruno Cassirer Verlag},
 language={ger},
 type={Text},
 title={Zur Einstein'schen Relativitätstheorie : erkenntnistheoretische Betrachtungen},
 URL={http://www.rcin.org.pl/impan/Content/5846/PDF/WA35_13785_5000_Zur-Einsteinschen.pdf},
}