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Fan AZ, Li Y, Elam-Evans LD, Balluz L.Fan AZ, et al.Clin Epidemiol. 2013;5:21-7. doi: 10.2147/CLEP.S12152. Epub 2013 Jan 29.Clin Epidemiol. 2013.PMID: 23390368Free PMC article.
Jones CP, Truman BI, Elam-Evans LD, Jones CA, Jones CY, Jiles R, Rumisha SF, Perry GS.Jones CP, et al.Ethn Dis. 2008 Autumn;18(4):496-504.Ethn Dis. 2008.PMID: 19157256