Columbia subject headings:
Russians--Foreign countries.
Harvard subject headings:
Russians--Foreign countries--History--20th century
Russians--Foreign countries.
Russians--Political activity--Foreign countries.
Soviet Union--Emigration and immigration--History.
Soviet Union--Emigration and immigration.
Princeton subject headings:
Russians--Foreign countries--History--20th century.
Russians--Foreign countries--Political activity.
Soviet Union--Emigration and immigration.