Não informado. (1945). Down to earth: A review of agricultural chemical progress. Down Chemical, Agricultural Products Department.
Chicago-referens (17:e uppl.)Não informado. Down to Earth: A Review of Agricultural Chemical Progress. Midland, Mich: Down Chemical, Agricultural Products Department, 1945.
MLA-referens (8:e uppl.)Não informado. Down to Earth: A Review of Agricultural Chemical Progress. Down Chemical, Agricultural Products Department, 1945.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.