https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-9-2
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-9-1
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-9-4
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-9-3