https://aoemj.biomedcentral.com/articles/10.1186/s40557-015-0061-4
https://aoemj.biomedcentral.com/articles/10.1186/s40557-015-0060-5
https://aoemj.biomedcentral.com/articles/10.1186/s40557-015-0059-y
https://aoemj.biomedcentral.com/articles/10.1186/s40557-015-0057-0