title: A virus released by "nonproducing" Rous sarcoma cells.
mesh_terms: D000818:Animals; D001354:Avian Leukosis Virus; D001358:Avian Sarcoma Viruses / Q000254:growth & development*; D001717:Birds; D002642:Chick Embryo; D005347:Fibroblasts; D014776:Virus Cultivation