Columbia subject headings:
Saudi Arabia--Boundaries--Yemen (Republic)
Saudi Arabia--Foreign relations--Yemen (Republic)
Yemen (Republic)--Boundaries--Saudi Arabia.
Yemen (Republic)--Foreign relations--Saudi Arabia.
Harvard subject headings:
Saudi Arabia--Boundaries--Yemen (Republic)
Saudi Arabia--Foreign relations--Yemen (Republic)
Yemen (Republic)--Boundaries--Saudi Arabia
Yemen (Republic)--Foreign relations--Saudi Arabia.
Princeton subject headings: