@misc{Kneser_Adolf_(1862–1930)_Lehrbuch_1900,
 author={Kneser, Adolf (1862–1930)},
 copyright={Public Domain},
 address={Braunschweig},
 howpublished={online},
 year={1900},
 publisher={Friedrich Vieweg und Sohn},
 language={ger},
 title={Lehrbuch der Variationsrechnung},
 type={Text},
 URL={http://rcin.org.pl/Content/80063/PDF/WA35_14006_4761_Lehrbuch.pdf},
}