Sitaraman and Friedman's essentials of gastroenterology / edited by Shanthi Srinivasan, MD, Professor of Medicine, Division of Digestive Diseases, Emory University School of Medicine; Chief of Gastroenterology, Atlanta Veterans Affairs Medical Center, Atlanta, GA, USA, Lawrence S. Friedman, MD, Professor of Medicine, Harvard Medical School, Boston; Professor of Medicine, Tufts University School of Medicine, Boston; The Anton R. Fried, MD, Chair, Department of Medicine, Newton-Wellesley Hospital, Newton; Assistant Chief of Medicine, Massachusetts General Hospital, Boston, MA, USA ; forward by Frank A. Anania, MD, FACP, AGAF, FAASLD, R. Bruce Logue Chair and Professor of Medicine, Director, Division of Digestive Diseases, Emory University Department of Medicine, Atlanta, GA, USA.