https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0108-9
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0112-0
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0109-8
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0110-2
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0113-z
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0111-1