https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-6-52
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-6-50
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-6-54
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-6-51
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-6-53