https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID3950757_code410506.pdf?abstractid=3909166&mirid=1
https://www.politico.eu/article/shaky-grounds-secret-slipshod-evidence-eu-use-sanction-russia-oligarchs/
http://visionofhumanity.org/app/uploads/2017/06/GPI-2017-Report-1.pdf