https://www.kommersant.ru/doc/3534031
On Jan. 29, 2018, a U.S. EP-3 Aries aircraft flying in international airspace over the Black Sea was intercepted by a Russian Su-27. This interaction was determined to be unsafe due to the Su-27 closing to within five feet and crossing directly through the EP-3’s flight path, causing the EP-3 to fly through the Su-27’s jet wash. The duration of the intercept lasted two hours and 40 minutes.
http://www.c6f.navy.mil/news/us-ep-3-intercepted-black-sea
http://www.pism.pl/publikacje/komentarz/nr-7-2018
https://www.radiosvoboda.org/a/donbass-realii/29003397.html
http://newsader.com/42500-s-segodnyashnego-dnya-ssha-nachnut-vvodit/
http://www.ng.ru/news/606445.html
https://newtimes.ru/articles/detail/143450
http://expert.ru/expert/2018/05/rost-iz-poslednih-sil/
https://www.novayagazeta.ru/articles/2018/01/29/75312-otstayuschee-razvitie