Columbia subject headings:
Migrant labor--Congresses.
Migration, Internal--Congresses.
Rural-urban migration--Congresses.
Harvard subject headings:
Migrant labor--Congresses.
Migration, Internal--Congresses
Rural-urban migration--Congresses.
Princeton subject headings:
Migrant labor--Congresses.
Migration, Internal--Congresses.
Rural-urban migration--Congresses.