@inbook{1206486203, author={Shivani Patel and Scott Roberts and Vanessa Rogers and Ashley Zink and Elaine Duryea and Jamie Morgan}, title={Preterm Birth}, booktitle={Williams Obstetrics Study Guide, 25e}, publisher={McGraw-Hill Education}, address={New York, NY}, year={2019}, url={obgyn.mhmedical.com/content.aspx?aid=1206486203} }