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Written informed consent and selection bias in observational studies using medical records: systematic review

Michelle E Kho1, Mark Duffett, Donald J Willison

  • 1Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4L8. khome@mcmaster.ca

BMJ (Clinical Research Ed.)
|March 14, 2009
PubMed
Abstract

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