@inbook{1184195373, author={Jonah J. Stulberg and Elliott R. Haut}, editor={Livingston, Edward H. and Lewis, Roger J.}, title={Practical Guide to Surgical Data Sets: Healthcare Cost and Utilization Project National Inpatient Sample (NIS)}, booktitle={JAMA Guide to Statistics and Methods}, publisher={McGraw-Hill Education}, address={New York, NY}, year={2019}, url={jamaevidence.mhmedical.com/content.aspx?aid=1184195373} }