Columbia subject headings:
Ethiopia--Foreign relations--Sudan.
Sudan--Foreign relations--Ethiopia.
Water security--Ethiopia.
Water security--Sudan.
Harvard subject headings:
Ethiopia--Foreign relations--Sudan.
Nile River Valley--Economic aspects.
Nile River Valley--Political aspects.
Nile River Valley--Strategic aspects.
Sudan--Foreign relations--Ethiopia.
Water resources development--Nile River Valley.
Princeton subject headings: