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Chen W, Zhu XH, Thulborn KR, Ugurbil K.Chen W, et al. Among authors: zhu xh.Proc Natl Acad Sci U S A. 1999 Mar 2;96(5):2430-4. doi: 10.1073/pnas.96.5.2430.Proc Natl Acad Sci U S A. 1999.PMID: 10051659Free PMC article.