https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-4-13
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-4-15
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-4-12
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-4-14
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-4-16