Columbia subject headings:
Industrial location--Pennsylvania--Philadelphia Metropolitan Area.
Philadelphia Metropolitan Area (Pa.)--Economic conditions.
Regional planning--Pennsylvania--Philadelphia Metropolitan Area.
Harvard subject headings:
Industrial location--Pennsylvania--Philadelphia Metropolitan Area.
Philadelphia Metropolitan Area (Pa.)--Economic conditions.
Regional planning--Pennsylvania--Philadelphia Metropolitan Area.
Princeton subject headings:
Industrial location--Pennsylvania--Philadelphia Metropolitan Area.
Philadelphia Metropolitan Area (Pa.)--Economic conditions.
Regional planning--Pennsylvania--Philadelphia Metropolitan Area.