https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-4 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-6 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-8 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-5 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-2 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-1 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-3 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-7 https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-9-9