Columbia subject headings:
Nigeria--Foreign relations--1960-
Harvard subject headings:
Nigeria--Foreign economic relations--Congresses.
Nigeria--Foreign relations--1960---Congresses.
Nigeria--Politics and government--1960---Congresses.
Princeton subject headings:
Nigeria--Foreign economic relations--Congresses.
Nigeria--Foreign relations--1960---Congresses.
Nigeria--Politics and government--1960---Congresses.