@inbook{57793693, author={Donald V. Byars and Barry J. Knapp}, editor={Ma, O. John and Mateer, James R. and Reardon, Robert F. and Joing, Scott A.}, title={Chapter 15. Second and Third Trimester Pregnancy}, booktitle={Ma and Mateer's Emergency Ultrasound, 3e}, publisher={The McGraw-Hill Companies}, address={New York, NY}, year={2014}, url={accessemergencymedicine.mhmedical.com/content.aspx?aid=57793693} }