http://www.rightcare.nhs.uk/atlas/
http://www.guardian.co.uk/news/datablog/2010/nov/25/health-health
http://www.e-health-insider.com/news/6453/healthcare_atlas_maps_nhs_variations
http://trusttheevidence.net/ami-banerjee/variation-and-inequality-what-are-the-causes/101126122