Columbia subject headings:
Capital.
Economics, Mathematical.
Industries--United States.
Supply and demand.
Wages--United States.
Working class--United States.
Harvard subject headings:
Capital.
Economics, Mathematical.
Industries--United States
Labor--United States
Supply and demand.
Wages--United States.
Working class--United States
Princeton subject headings:
Capital.
Economics, Mathematical.
Industries--United States.
Labor--United States.
Supply and demand.
Wages--United States.