Não informado. (1942). Plant science literature. U.S. Department of Agriculture, Bureau of Plant Industry.
Chicago-referens (17:e uppl.)Não informado. Plant Science Literature. Washington: U.S. Department of Agriculture, Bureau of Plant Industry, 1942.
MLA-referens (8:e uppl.)Não informado. Plant Science Literature. U.S. Department of Agriculture, Bureau of Plant Industry, 1942.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.