Columbia subject headings:
Labor supply--Developing countries.
Poor--Developing countries.
Proletariat.
Working class--Developing countries.
Harvard subject headings:
Labor supply--Developing countries.
Poor--Developing countries
Proletariat.
Working class--Developing countries
Princeton subject headings:
Labor supply--Developing countries.
Labor--Developing countries.
Poor--Developing countries.
Proletariat.