Columbia subject headings:
Canal Zone--Economic conditions.
Canal Zone--Strategic aspects.
Canal Zone.
Military bases, American--Panama--Canal Zone.
Panama Canal (Panama)
Panama Canal (Panama)--History.
Panama Canal (Panama)--Strategic aspects.
Panama--Foreign relations--United States.
United States--Foreign relations--Panama.
Harvard subject headings:
Canal Zone--Economic conditions.
Canal Zone--Strategic aspects.
Military bases, American--Panama--Canal Zone.
Panama Canal (Panama)--History.
Panama Canal (Panama)--Strategic aspects.
Panama--Foreign relations--United States.
United States--Foreign relations--Panama.
Princeton subject headings:
Canal Zone--Economic conditions.
Canal Zone--Strategic aspects.
Military bases, American--Panama--Canal Zone.
Panama Canal (Panama)--History.
Panama Canal (Panama)--Strategic aspects.
Panama--Foreign relations--United States.
United States--Foreign relations--Panama.