1. Stanford University School of Medicine; Division of Gastroenterology & Hepatology; Alway Building, M211, 300 Pasteur Drive Stanford California USA 94305
2. Johns Hopkins University; Division of Gastroenterology & Hepatology, Department of Medicine; Baltimore MD USA
3. 16847 Colven Road Granada Hills CA USA CA 91344
4. Olive View-UCLA Medical Center; Department of Medicine; 14445 Olive View Drive Sylmar California USA 91342
5. Johns Hopkins University; Welch Medical Library; 2024 E Monument Street Baltimore USA
6. Perelman School of Medicine, University of Pennsylvania; Department of Biostatistics and Epidemiology; 423 Guardian Drive Philadelphia USA