[1] Med Univ Vienna, Div Gastroenterol & Hepatol, Gastroenterol & Hepatol Abt, Dept Med 3, A-1090 Vienna, Austria
[2] Multi Profile Hosp Act Treatment Queen Joanna, Sofia, Bulgaria
[3] City Hosp N26, St Petersburg, Russia
[4] Crimean Med Univ, Simferopo, Ukraine
[5] Katedra Gastroenterol, Warsaw, Poland
[6] Klin Gastroenterol, Warsaw, Poland
[7] Hosp Cent Dr Ignacio Morones Prieto, Mexico City, DF, Mexico
[8] Hosp Gastroenterol Dr Carlos Bonorino Udaondo, Buenos Aires, DF, Argentina
[9] Imeldaziekenhuis, Bonheiden, Belgium