https://joppp.biomedcentral.com/articles/10.1186/s40545-016-0094-2
https://joppp.biomedcentral.com/articles/10.1186/s40545-016-0095-1
https://joppp.biomedcentral.com/articles/10.1186/s40545-016-0093-3
https://joppp.biomedcentral.com/articles/10.1186/s40545-016-0096-0