Columbia subject headings:
History--Statistical methods.
History--Study and teaching (Higher)--United States.
United States--Politics and government--20th century.
Harvard subject headings:
History--Statistical methods
History--Study and teaching (Higher)--United States
United States--Politics and government--20th century.
Princeton subject headings:
History--Statistical methods.
History--Study and teaching (Higher)--United States.
United States--Politics and government--20th century.