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Groisman EA, Sturmoski MA, Solomon FR, Lin R, Ochman H.Groisman EA, et al. Among authors: ochman h.Proc Natl Acad Sci U S A. 1993 Feb 1;90(3):1033-7. doi: 10.1073/pnas.90.3.1033.Proc Natl Acad Sci U S A. 1993.PMID: 8430070Free PMC article.