https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-25
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-27
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-26
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-28