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Lansdorp PM, Smith C, Safford M, Terstappen LW, Thomas TE.Lansdorp PM, et al.Cytometry. 1991;12(8):723-30. doi: 10.1002/cyto.990120806.Cytometry. 1991.PMID: 1794253Free article.
Curtis JR, McClure LA, Delzell E, Howard VJ, Orwoll E, Saag KG, Safford M, Howard G.Curtis JR, et al.J Gen Intern Med. 2009 Aug;24(8):956-62. doi: 10.1007/s11606-009-1031-8. Epub 2009 Jun 24.J Gen Intern Med. 2009.PMID: 19551449Free PMC article.