Columbia subject headings:
Arid regions--Brazil, Northeast.
Sustainable development--Brazil, Northeast.
Water resources development--Brazil, Northeast.
Harvard subject headings:
Arid regions--Brazil, Northeast.
Environmental education--Brazil, Northeast.
Sustainable development--Brazil, Northeast.
Water resources development--Brazil, Northeast
Princeton subject headings:
Arid regions--Brazil, Northeast.
Sustainable development--Brazil, Northeast.
Water resources development--Brazil, Northeast.