https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-2
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-3
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-4
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-8-1