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Craig SP 3rd, Yuan L, Kuntz DA, McKerrow JH, Wang CC.Craig SP 3rd, et al. Among authors: mckerrow jh.Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2500-4. doi: 10.1073/pnas.88.6.2500.Proc Natl Acad Sci U S A. 1991.PMID: 2006185Free PMC article.