http://libraryqno7mkjsntq434rk3t6ncieqx34tlqxisxdv6e552ab6uolyd.onion/library/crimethinc-1919-when-the-bolsheviks-turned-on-the-workers
Dmitri Volkogonov, Shukman, Harold, ed., Trotsky: The Eternal Revolutionary, London: HarperCollins, p.180. 1996. Nicolas Werth, Karel Bartosek, Jean-Louis Panne, Jean-Louis Margolin, Andrzej Paczkowski, Stephane Courtois, The Black Book of Communism: Crimes, Terror, Repression.