1. Faculty of Medicine, Pontificia Universidad Católica de Chile; Department of Internal Medicine, Evidence Based Health Care Program; Lira 44, Santiago Santiago Región metropolitana Chile
2. Schulich School of Medicine & Dentistry, University of Western Ontario; Departments of Anesthesia & Perioperative Medicine, Epidemiology & Biostatistics; University Hospital, Room C3-173 339 Windermere Road London Ontario Canada N6A 5A5
3. Northwestern University Feinberg Medical School; Division of Gastroenterology; Suite 1400 676 N. St. Clair Avenue Chicago Illinois USA IL 60611
4. McMaster University; Department of Medicine, Division of Gastroenterology; 1280 Main Street West Hamilton Ontario Canada L8S 4K1