Columbia subject headings:
Delaware River Valley (N.Y.-Del. and N.J.)--Economic conditions.
Water resources development--Environmental aspects--Delaware River Valley (N.Y.-Del. and N.J.)
Harvard subject headings:
Delaware River Valley (N.Y.-Del. and N.J.)--Economic conditions.
Water resources development--Environmental aspects--Delaware River Valley (N.Y.-Del. and N.J.)
Princeton subject headings:
Delaware River Valley (N.Y.-Del. and N.J.)--Economic conditions.
Water resources development--Environmental aspects--Delaware River Valley (N.Y.-Del. and N.J.).