Columbia subject headings:
Ecuador--Foreign relations--Peru.
Peru--Foreign relations--Ecuador.
Water resources development--Tumbes River (Ecuador and Peru)
Harvard subject headings:
Ecuador--Foreign relations--Peru.
Peru--Foreign relations--Ecuador.
Water resources development--Tumbes River (Ecuador and Peru)
Princeton subject headings:
Water resources development--International cooperation.
Water resources development--Tumbes River (Ecuador and Peru).
Water use--International cooperation.
Water use--Tumbes River (Ecuador and Peru).