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Hurley LS, Duncan JR, Sloan MV, Eckhert CD.Hurley LS, et al.Proc Natl Acad Sci U S A. 1977 Aug;74(8):3547-9. doi: 10.1073/pnas.74.8.3547.Proc Natl Acad Sci U S A. 1977.PMID: 269412Free PMC article.