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Zanotto PM, Gould EA, Gao GF, Harvey PH, Holmes EC.Zanotto PM, et al. Among authors: holmes ec.Proc Natl Acad Sci U S A. 1996 Jan 23;93(2):548-53. doi: 10.1073/pnas.93.2.548.Proc Natl Acad Sci U S A. 1996.PMID: 8570593Free PMC article.