Columbia subject headings:
Egypt--Foreign relations--Sudan.
Libya--Foreign relations--Egypt.
Libya--Foreign relations--Sudan.
Sudan--Foreign relations--Libya.
Harvard subject headings:
Egypt--Foreign relations--Sudan.
Libya--Foreign relations--Egypt.
Libya--Foreign relations--Sudan.
Sudan--Foreign relations--Libya.
Princeton subject headings:
Egypt--Foreign relations--Sudan.
Libya--Foreign relations--Egypt.
Libya--Foreign relations--Sudan.
Sudan--Foreign relations--Libya.