Não informado. (1941). Conservation bulletin of the Fish Wildlife Service, United States. U.S. Fish and Wildlife Service.
Chicago-referens (17:e uppl.)Não informado. Conservation Bulletin of the Fish Wildlife Service, United States. Washington: U.S. Fish and Wildlife Service, 1941.
MLA-referens (8:e uppl.)Não informado. Conservation Bulletin of the Fish Wildlife Service, United States. U.S. Fish and Wildlife Service, 1941.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.