1. Department of GastroenterologyHospital San Pedro de AlcantaraCaceresSpain
2. Division of Gastroenterology and HepatologyCentre Hospitalier Universitaire Vaudois et Université de LausanneLausanneSwitzerland
3. Department of GastroenterologyHospital General de TomellosoTomellosoSpain
4. Center for Esophageal Diseases and SwallowingDivision of Gastroenterology and HepatologyUniversity of North Carolina School of MedicineChapel HillNCUSA