Não informado. (2008). The University of Iowa Studies in Natural History. University of Iowa.
Chicago-referens (17:e uppl.)Não informado. The University of Iowa Studies in Natural History. Iowa City, Iowa: University of Iowa, 2008.
MLA-referens (8:e uppl.)Não informado. The University of Iowa Studies in Natural History. University of Iowa, 2008.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.