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Abu-Raddad LJ, Sabatelli L, Achterberg JT, Sugimoto JD, Longini IM Jr, Dye C, Halloran ME.Abu-Raddad LJ, et al.Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):13980-5. doi: 10.1073/pnas.0901720106. Epub 2009 Aug 3.Proc Natl Acad Sci U S A. 2009.PMID: 19666590Free PMC article.