ov . ▁ ▁After ▁publishing ▁Abd ur akh man ▁Av t ork han ov ' s ▁book ▁St alin ▁and ▁the ▁Soviet ▁Commun ist ▁Party : ▁A ▁Study ▁in ▁the ▁Technology ▁of ▁Power , ▁Gr ig oren ko ▁made ▁and ▁distributed ▁its ▁copies ▁by ▁photograph ing ▁and ▁type writing . ▁In ▁ 1 9 7 6 , ▁Gr ig oren ko ▁helped ▁found ▁the ▁Moscow ▁Hels ink i ▁Group ▁and ▁the ▁Ukrain ian ▁Hels ink i ▁Group . ▁ ▁In ▁the ▁United ▁States ▁On ▁ 2 0 ▁December ▁ 1 9 7 7 , ▁Gr ig oren ko ▁was ▁allowed ▁to ▁go ▁abroad ▁for ▁medical ▁treatment . ▁His ▁health ▁was ▁ru ined ▁during ▁for cible ▁conf in ement ▁in ▁K GB - run ▁mental ▁hosp it als . ▁On ▁ 3 0 ▁November ▁ 1 9 7 7 , ▁Gr ig oren ko ▁arrived ▁in ▁the ▁United ▁States ▁and ▁was ▁stri pped ▁of ▁his ▁Soviet ▁citizens hip . ▁In ▁Gr ig oren ko ' s ▁words , ▁Leon id ▁Bre zh ne v ▁signed ▁the ▁dec ree ▁of ▁dep riv ing ▁Gr ig oren ko ▁of ▁Soviet ▁citizens hip ▁on ▁the ▁ground ▁that ▁he ▁was ▁und erm ining ▁the ▁prest ige ▁of ▁the ▁Soviet ▁Union . ▁The ▁ 1 9 7 0 s ▁marked ▁a ▁peak ▁in ▁the ▁use ▁of ▁external ▁ex ile ▁as ▁a ▁pun itive ▁measure ▁by ▁the ▁Soviet ▁Union ▁( as ▁opposed ▁to ▁the ▁internal ▁type , ▁which ▁was ▁highest ▁between ▁the ▁mid - 1 9 3 0 s ▁and