https://joppp.biomedcentral.com/articles/10.1186/s40545-015-0034-6
https://joppp.biomedcentral.com/articles/10.1186/s40545-015-0033-7
https://joppp.biomedcentral.com/articles/10.1186/s40545-015-0032-8
https://joppp.biomedcentral.com/articles/10.1186/s40545-015-0035-5