1. Gastroenterology, Pontificia Universidad Católica de Chile, Santiago, Chile
2. Gastroenterology, “Prof. Henry Cohen”, Hospital de Clinicas de Montevideo, Montevideo, Uruguay
3. Digestive Diseases Centre, Nottingham University Hospitals, Nottingham, United Kingdom
4. Gastroenterology, Hospital Universitario Central de Asturias, Oviedo, Spain