Não informado. Plant Immigrants. U.S. Department of Agriculture, Bureau of Plant Industry.
Chicago-referens (17:e uppl.)Não informado. Plant Immigrants. Washington: U.S. Department of Agriculture, Bureau of Plant Industry.
MLA-referens (8:e uppl.)Não informado. Plant Immigrants. U.S. Department of Agriculture, Bureau of Plant Industry.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.