@misc{Esper_Eugen_Johann_Christoph_(1742–1810)_Der_[post,
 author={Esper, Eugen Johann Christoph (1742–1810) and Walther, Wolfgang (17..-17..). Wyd},
 editor={Walther, Wolfgang (17..-17..). Wyd},
 copyright={Public Domain},
 address={[Erlangen]},
 howpublished={online},
 year={[post 1776]},
 publisher={im Verlage Wolfgang Walthers},
 language={ger},
 title={Der europaischen Schmetterlinge. T. 4, cz. 2},
 URL={http://www.rcin.org.pl/Content/56189/PDF/WA058_74414_K5048-6_Schmetter-Abbild-Eug.pdf},
 keywords={early printed books, Lepidoptera, butterflies, early works to 1800},
}