Columbia subject headings:
Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Russia)--History.
Soviet Union--History--Revolution, 1917-1921.
Harvard subject headings:
Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Russia)--History.
Soviet Union--History--Revolution, 1917-1921.
Princeton subject headings:
Petropavlovskai︠a︡ krepostʹ (Saint Petersburg, Russia)--History.
Soviet Union--History--Revolution, 1917-1921.