@misc{Forsyth_Andrew_Russell._Lehrbuch,
 author={Forsyth, Andrew Russell. and Maser, Hermann. and Jacobsthal, Walter.},
 howpublished={online},
 publisher={Friedrich Vieweg und Sohn},
 language={ger},
 type={książka},
 type={dokument piśmienniczy},
 title={Lehrbuch der Differental-Gleichungen},
}