Columbia subject headings:
Depressions--1929--History.
Depressions--1930--History.
Soviet Union--Commerce--History.
Soviet Union--Economic policy--1928-1932.
Harvard subject headings:
Depressions--1929--History.
Depressions--1930--History.
Soviet Union--Commerce--History.
Soviet Union--Economic policy--1928-1932.
Princeton subject headings: