title: Isolation of an avian leukosis virus associated with the Harris strain of Rous sarcoma virus.
mesh_terms: D001354:Avian Leukosis Virus / Q000302:isolation & purification*; D001358:Avian Sarcoma Viruses; D046508:Culture Techniques; D003673:Defective Viruses; D006378:Helper Viruses / Q000302:isolation & purification