@inbook{1000028367, author={Norton J. Greenberger and Richard S. Blumberg and Robert Burakoff}, title={}, booktitle={CURRENT Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy, 2e}, publisher={The McGraw-Hill Companies}, address={New York, NY}, year={2012}, url={accessmedicine.mhmedical.com/content.aspx?aid=1000028367} }