Columbia subject headings:
Democracy--History--20th century.
Democracy--History--21st century.
Democratization--History--20th century.
Democratization--History--21st century.
Harvard subject headings:
Democracy--History--20th century
Democracy--History--21st century.
Democratization--History--20th century.
Democratization--History--21st century.
Princeton subject headings:
Democratization--Case studies.
Democratization--History--20th century.
Democratization--History--21st century.
Regime change--Case studies.
Regime change--History--20th century.
Regime change--History--21st century.