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Fong D, Calhoun DH, Hsieh WT, Lee B, Wells RD.Fong D, et al.Proc Natl Acad Sci U S A. 1986 May;83(9):2909-13. doi: 10.1073/pnas.83.9.2909.Proc Natl Acad Sci U S A. 1986.PMID: 3010323Free PMC article.