Director of Research Center for Foreign Military Studies U.S. Army Lieutenant Colonel U.S. Army LW Grau and the U.S. Air Force Capt. DK Drenkovski personally participated in Operation Linebacker II, in his special work devoted to this operation , note that , no matter how awesome it is did not seem at first glance , but the most objective picture and comments to give this operation it was the Soviet military experts seconded to the parts of the VNA defense . The authors cite articles mainly Colonel General AI Hyupenena , published in the " Journal of Military History ." The only point where Hyupenen could , in their view , a little " slukavit " is its relatively low evaluation of the effectiveness of combat use of American anti-radar missiles . So there is reason to believe they Drenkovski after talking with one of the returning American prisoners of war in the United States , which at the time of its transportation through the territory of the DRV in the center of Hanoi drew attention to the large concentration of metal that looks like a two-way cab of the Soviet air defense system , which he averaged about four , many of whom , according to a former prisoner , had traces of defeat missiles AGM- 45 Shrike and AGM- 78 Standard ARM . Given that, from April 1965 to December 1974 . The Soviet Union supplied to Vietnam 95 anti-aircraft missiles SA- 75M : 92 - trehkabinnogo options and 3 - shestikabinnyh (of 312 units of cabins , including 95 receiving and transmitting booths "P" ) , it turns out that an American prisoner of war, was able to count on 38 SAM broken more than there were in the SMP VNA for the entire period of the war.