Columbia subject headings:
Self-employed--Developing countries.
Self-employed--Europe.
Self-employed--United States.
Self-employed.
Harvard subject headings:
Self-employed
Self-employed--Developing countries.
Self-employed--Europe.
Self-employed--United States
Princeton subject headings:
Self-employed--Developing countries.
Self-employed--Europe.
Self-employed--United States.
Self-employed.