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Vasiliev JM, Gelfand IM, Guelstein VI.Vasiliev JM, et al. Among authors: guelstein vi.Proc Natl Acad Sci U S A. 1971 May;68(5):977-9. doi: 10.1073/pnas.68.5.977.Proc Natl Acad Sci U S A. 1971.PMID: 5280531Free PMC article.