1. Department of Gastroenterology, Hospital of the Ministry of Internal Affairs, Szczecin, Poland
2. Department of Gastroenterology, Helios Frankenwaldklinik, Kronach, Germany
3. Department of Gastroenterology, Ameos Teaching University Hospital (Otto-von-Guericke University – Magdeburg), Halberstadt, Germany
4. University of Belgrade, Belgrade, Serbia
5. Department of Gastroenterology “Prof. Carolina Olano”, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay