@inbook{2642545,
author={Brenda Waning and Michael Montagne},
title={Chapter 3. Observational Study Designs},
booktitle={Pharmacoepidemiology: Principles and Practice},
publisher={The McGraw-Hill Companies},
address={New York, NY},
year={2001},
url={accesspharmacy.mhmedical.com/content.aspx?aid=2642545}
}