https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-98 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-99 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-101 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-103 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-97 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-100 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-11-102