http://www.bbc.com/news/world-europe-40653756
https://publications.parliament.uk/pa/ld201719/ldselect/ldeucom/16/1603.htm
http://hmics.org/sites/default/files/publications/HMICS20170621PUB.pdf
https://www.washingtonpost.com/world/europe/russian-submarines-are-prowling-around-vital-undersea-cables-its-making-nato-nervous/2017/12/22/d4c1f3da-e5d0-11e7-927a-e72eac1e73b6_story.html?utm_term=.e39e8fb9dafe