https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-7-8
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-7-6
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-7-5
https://health-policy-systems.biomedcentral.com/articles/10.1186/1478-4505-7-7