https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-55
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-57
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-59
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-56
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-60
https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-7-58