https://www.gazeta.ru/business/2019/04/12/12298945.shtml
http://www.kasparov.ru/material.php?id=5CB056CA632C0
https://jamestown.org/program/vega-strategic-services-russian-pmcs-as-part-of-information-warfare/
https://nv.ua/opinion/ne-tolko-dzhaveliny-kogda-evropa-zashchitit-ukrainu-50015863.html
https://www.gazeta.ru/business/2019/04/10/12294151.shtml
https://www.gazeta.ru/army/2019/04/10/12294691.shtml