Não informado. Regulatory Announcement. U.S. Fish and Wildlife Service.
Chicago-referens (17:e uppl.)Não informado. Regulatory Announcement. Washington: U.S. Fish and Wildlife Service.
MLA-referens (8:e uppl.)Não informado. Regulatory Announcement. U.S. Fish and Wildlife Service.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.