https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0265-2
https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0262-5
https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0258-1
https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0263-4
https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0261-6
https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-015-0264-3