https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0139-2
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0141-8
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0137-4
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0142-7
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0138-3
https://human-resources-health.biomedcentral.com/articles/10.1186/s12960-016-0140-9