Title: Chekisty Petrograda na strazhe revoli︠u︡t︠s︡ii
Subjects: Russian S.F.S.R., Secret service, Russian S.F.S.R. Chrezvychaĭnai︠a︡ komissii︠a︡ po borʹbe s kontr-revoli︠u︡t︠s︡ieĭ i sabotazhem, History