@inbook{1106704135, author={Arthur C. Fleischer}, editor={Fleischer, Arthur C. and Toy, Eugene C. and Lee, Wesley and Manning, Frank A. and Romero, Roberto J.}, title={TRANSVAGINAL SONOGRAPHY OF EARLY INTRAUTERINE PREGNANCY}, booktitle={Sonography in Obstetrics and Gynecology: Principles & Practice, 7e}, publisher={McGraw-Hill Education}, address={New York, NY}, year={2015}, url={obgyn.mhmedical.com/content.aspx?aid=1106704135} }