Columbia subject headings:
Universities and colleges--Curricula--United States.
Universities and colleges--United States--Elective system.
Harvard subject headings:
Universities and colleges--Curricula--United States--History.
Universities and colleges--Curricula--United States.
Universities and colleges--United States--Elective system--History.
Universities and colleges--United States--Elective system.
Princeton subject headings:
Universities and colleges--Curricula--United States.
Universities and colleges--United States--Elective system.