@inbook{1160776228, author={F. Gary Cunningham and Kenneth J. Leveno and Steven L. Bloom and Jodi S. Dashe and Barbara L. Hoffman and Brian M. Casey and Catherine Y. Spong}, title={Operative Vaginal Delivery}, booktitle={Williams Obstetrics, 25e}, publisher={McGraw-Hill Education}, address={New York, NY}, year={2018}, url={accessmedicine.mhmedical.com/content.aspx?aid=1160776228} }