@misc{Beal_Foster_Ellenborough_Lascelles_Cuckoos,
 author={Beal, Foster Ellenborough Lascelles and Judd, Silvester D.},
 howpublished={online},
 publisher={Government Printing Office},
 language={eng},
 type={szkice},
 title={Cuckoos and shrikes in their relation to agriculture},
 keywords={ptaki},
}