https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-9-12
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-9-13
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-9-15
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-9-14