https://www.kommersant.ru/doc/3313871
https://www.depo.ua/ukr/war/nas-chekaye-garyacha-faza-viyni-scho-z-cim-robiti-20170531581029
https://lenta.ru/articles/2017/05/31/sochi/
https://lenta.ru/articles/2017/05/31/arctech/
https://www.gazeta.ru/army/2017/05/31/10700495.shtml
https://www.kommersant.ru/doc/3312958
http://inosmi.ru/military/20170530/239466642.html
Simple: attack AWACS, various intelligence, surveillance and reconnaissance (ISR) assets, aerial refueling tankers and electronic attack aircraft in the sky.
https://lenta.ru/news/2017/05/29/bmp/
https://lenta.ru/articles/2017/05/29/command/