https://www.kommersant.ru/doc/3843624
https://www.inopressa.ru/article/25Dec2018/newsweek/attack.html
https://www.rbc.ru/newspaper/2018/12/25/5c20e0939a7947cfc382f1be
https://www.kommersant.ru/doc/3842326
Regional experts also predicted that Russia may look to take advantage of the uncertainty created by James Mattis's resignation as President Trump's defense secretary.
https://www.newsweek.com/ukraine-russia-war-attack-christmas-1270621
https://www.gazeta.ru/army/2018/12/24/12106177.shtml
https://www.gazeta.ru/politics/2018/12/24_a_12106369.shtml
http://www.kasparov.ru/material.php?id=5C20BC4282C5D
http://expert.ru/expert/2019/01/simptomyi-novogo-mira/
https://www.rbc.ru/newspaper/2018/12/24/5c1d29539a794781b1a778d9