title: Longevity of strains from individual foci of human amnion cells transformed by simian virus 40.
mesh_terms: D000650:Amnion / Q000382:microbiology*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D006801:Humans; D013539:Simian virus 40 / Q000472:pathogenicity*; D013997:Time Factors