Columbia subject headings:
Executive power.
Heads of state--Statistics.
Heads of state--Term of office--Case studies.
Political leadership.
Power (Social sciences)
World politics--19th century.
World politics--20th century.
Harvard subject headings:
Executive power.
Heads of state--Statistics.
Heads of state--Term of office--Case studies.
Political leadership.
Power (Social sciences)
World politics--19th century
World politics--20th century
Princeton subject headings:
Political leadership.
Power (Social sciences)