title: An avian leukosis virus related to RSV(O): properties and evidence for helper activity.
mesh_terms: D000818:Animals; D000941:Antigens / Q000032:analysis; D001717:Birds; D002471:Cell Transformation, Neoplastic; D002499:Centrifugation, Density Gradient; D002642:Chick Embryo; D002951:Citrates; D003168:Complement Fixation Tests
chemical_list: D000941:Antigens; D002951:Citrates