Columbia subject headings:
Harvard subject headings:
Liberty--Political aspects--History--21st century.
Political sociology--History--21st century.
Social change--History--21st century.
Social structure--History--21st century.
Princeton subject headings:
Liberty--Political aspects--History--21st century.
Political sociology--History--21st century.
Social change--History--21st century.
Social structure--History--21st century.