Columbia subject headings:
Entrepreneurship--History.
Industries--United States--History.
Inventions--United States--History.
Technological innovations--United States--History.
Harvard subject headings:
Entrepreneurship--History
Industries--United States--History
Inventions--United States--History
Technological innovations--United States--History
Princeton subject headings:
Entrepreneurship--History.
Industries--United States--History.
Inventions--United States--History.
Technological innovations--United States--History.