http://www.ips-journal.eu/regions/global/article/show/why-pollsters-normally-get-it-right-more-or-less-2299/
https://www.tasc.ie/download/pdf/18456_health_inequalities_finalweb.pdf
https://www.genengnews.com/news/icelands-aggressive-covid-19-testing-helped-curb-outbreak/