Columbia subject headings:
Soviet Union--Bibliography--Dictionaries.
Soviet Union--History--Revolution, 1917-1921--Chronology.
Harvard subject headings:
Reference works.
Soviet Union--Bibliography--Dictionaries.
Soviet Union--History--Revolution, 1917-1921--Chronology.
Soviet Union--History--Revolution, 1917-1921--Encyclopedias.
Princeton subject headings:
Soviet Union--Bibliography--Dictionaries.
Soviet Union--History--Revolution, 1917-1921--Chronology.