Não informado. Plant Immigrants. U.S. Department of Agriculture, Bureau of Plant Industry.
Chicago-viite (17. p.)Não informado. Plant Immigrants. Washington: U.S. Department of Agriculture, Bureau of Plant Industry.
MLA-viite (8. p.)Não informado. Plant Immigrants. U.S. Department of Agriculture, Bureau of Plant Industry.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.