Columbia subject headings:
Right and left (Political science)--Europe--History--20th century.
Right and left (Political science)--Latin America--History--20th century.
Socialism--Europe--History--20th century.
Socialism--Latin America--History--20th century.
Harvard subject headings:
Right and left (Political science)--Europe--History--20th century.
Right and left (Political science)--Latin America--History--20th century.
Socialism--Europe--History--20th century
Socialism--Latin America--History--20th century.
Princeton subject headings:
Right and left (Political science)--Europe--History--20th century.
Right and left (Political science)--Latin America--History--20th century.
Socialism--Europe--History--20th century.
Socialism--Latin America--History--20th century.