Não informado. (1955). Forest pest leaflet. U.S. Department of Agriculture, Forest Service.
Chicago-referens (17:e uppl.)Não informado. Forest Pest Leaflet. Washington: U.S. Department of Agriculture, Forest Service, 1955.
MLA-referens (8:e uppl.)Não informado. Forest Pest Leaflet. U.S. Department of Agriculture, Forest Service, 1955.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.