Columbia subject headings:
Nigeria--Economic conditions--1960---Congresses.
Nigeria--Population--Congresses.
Rural-urban migration--Nigeria--Congresses.
Urbanization--Nigeria--Congresses.
Harvard subject headings:
Nigeria--Economic conditions--1960---Congresses.
Nigeria--Population--Congresses.
Rural-urban migration--Nigeria--Congresses.
Urbanization--Nigeria--Congresses.
Princeton subject headings:
Nigeria--Economic conditions--Congresses.
Urbanization--Nigeria--Congresses.