@misc{Hegner_Robert_William_(1880–1942)_Invertebrate_1933,
 author={Hegner, Robert William (1880–1942)},
 copyright={Public Domain},
 address={New York},
 howpublished={online},
 year={1933},
 publisher={The Macmillan Company},
 language={eng},
 title={Invertebrate zoology},
 type={Text},
 URL={http://rcin.org.pl/Content/138674/PDF/WA488_173610_2019729_Invertebrate-zoology.pdf},
 keywords={Invertebrates, Invertebrate zoology - protozoa - porifera - molluscs - arthropods - echinoderms},
}