http://www.kasparov.ru/material.php?id=5C35E716C06BD
https://www.radiosvoboda.org/a/war-ukraine-2018/29691707.html
https://www.gazeta.ru/army/2018/12/29/12113083.shtml
http://www.kasparov.ru/material.php?id=5C24761BB6C67
https://www.gazeta.ru/army/2018/12/27/12110227.shtml
https://www.inopressa.ru/article/25Dec2018/newsweek/attack.html
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