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Card studies for observational research in practice.
Westfall JM, Zittleman L, Staton EW, Parnes B, Smith PC, Niebauer LJ, Fernald DH, Quintela J, Van Vorst RF, Dickinson LM, Pace WD. Westfall JM, et al. Among authors: niebauer lj. Ann Fam Med. 2011 Jan-Feb;9(1):63-8. doi: 10.1370/afm.1199. Ann Fam Med. 2011. PMID: 21242563 Free PMC article.