Columbia subject headings:
Human beings--Effect of environment on--Sahel.
Human ecology--Sahel.
Sahel--Economic conditions.
Harvard subject headings:
Human beings--Effect of environment on--Sahel.
Human ecology--Sahel.
Sahel--Economic conditions.
Princeton subject headings:
Human beings--Effect of environment on--Sahel.
Human ecology--Sahel.
Sahel--Economic conditions.