https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0147-2
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0146-3
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0144-5
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0145-4
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0148-1
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0143-6
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0150-7