Não informado. (1939). Contributions from the University of Michigan Herbarium. University of Michigan Herbarium.
Chicago-referens (17:e uppl.)Não informado. Contributions from the University of Michigan Herbarium. Ann Arbor, Mich: University of Michigan Herbarium, 1939.
MLA-referens (8:e uppl.)Não informado. Contributions from the University of Michigan Herbarium. University of Michigan Herbarium, 1939.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.