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Zheng C, Friedman DI.Zheng C, et al. Among authors: friedman di.Proc Natl Acad Sci U S A. 1994 Aug 2;91(16):7543-7. doi: 10.1073/pnas.91.16.7543.Proc Natl Acad Sci U S A. 1994.PMID: 8052617Free PMC article.