@inbook{1190761068, author={F. Gary Cunningham and Kenneth J. Leveno and Jodi S. Dashe and Barbara L. Hoffman and Catherine Y. Spong and Brian M. Casey}, title={Vaginal Delivery}, booktitle={Williams Obstetrics, 26e}, publisher={McGraw Hill}, address={New York, NY}, year={2022}, url={obgyn.mhmedical.com/content.aspx?aid=1190761068} }