@misc{Wieloch_Maria_Numbers_1984,
 author={Wieloch, Maria},
 editor={Polska Akademia Nauk. Instytut Zoologii},
 copyright={Rights Reserved - Free Access},
 address={Warszawa},
 journal={Acta Ornithologica},
 howpublished={online},
 year={1984},
 publisher={Państwowe Wydawnictwo Naukowe},
 language={eng},
 language={rus},
 language={pol},
 type={Text},
 title={Numbers and distribution of the mute swan Cygnus olor in Poland against the situation of this species in Europe},
 URL={http://rcin.org.pl./Content/37533/PDF/WA058_39859_P257-T20_Acta-Ornith-Nr-2-4.pdf},
 keywords={Mute Swan, counting, distribution, Poland, Europe, monograph, birds, Cygnus olor, Anatidae, Aves},
}