Não informado. (2000). University of Iowa studies in social science. University of Iowa.
Chicago-referens (17:e uppl.)Não informado. University of Iowa Studies in Social Science. Iowa City, Iowa: University of Iowa, 2000.
MLA-referens (8:e uppl.)Não informado. University of Iowa Studies in Social Science. University of Iowa, 2000.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.