Columbia subject headings:
Egypt--History--1919-
Egypt--Relations--Sudan.
Sudan--History--1820-
Sudan--Relations--Egypt.
Harvard subject headings:
Egypt--History--1919-
Egypt--Relations--Sudan.
Sudan--History--1899-1956
Sudan--Relations--Egypt.
Princeton subject headings:
Egypt--History--20th century.
Egypt--Relations--Sudan.
Sudan--History--1821-
Sudan--Relations--Egypt.