Não informado. (1919). University of Iowa Studies in Natural History. University of Iowa.
Chicago-Zitierstil (17. Ausg.)Não informado. University of Iowa Studies in Natural History. Iowa City, Iowa: University of Iowa, 1919.
MLA-Zitierstil (8. Ausg.)Não informado. University of Iowa Studies in Natural History. University of Iowa, 1919.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.