https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-10-46
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-10-43
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-10-45
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-10-44