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Slusher LB, Gillman EC, Martin NC, Hopper AK.Slusher LB, et al. Among authors: hopper ak.Proc Natl Acad Sci U S A. 1991 Nov 1;88(21):9789-93. doi: 10.1073/pnas.88.21.9789.Proc Natl Acad Sci U S A. 1991.PMID: 1946403Free PMC article.