Columbia subject headings:
Droughts--Niger.
Droughts--Sahel.
Famines--Niger.
Famines--Sahel.
Harvard subject headings:
Droughts--Niger.
Droughts--Sahel
Famines--Niger.
Famines--Sahel
Princeton subject headings:
Droughts--Niger.
Droughts--Sahel.
Famines--Niger.
Famines--Sahel.