Columbia subject headings:
Sanitation, Rural--Economic aspects--Yemen (Republic)
Sanitation, Rural--Social aspects--Yemen (Republic)
Water-supply, Rural--Economic aspects--Yemen (Republic)
Water-supply, Rural--Social aspects--Yemen (Republic)
Harvard subject headings:
Sanitation, Rural--Economic aspects--Yemen.
Sanitation, Rural--Social aspects--Yemen.
Water-supply, Rural--Economic aspects--Yemen.
Water-supply, Rural--Social aspects--Yemen.
Princeton subject headings:
Sanitation, Rural--Economic aspects--Yemen.
Sanitation, Rural--Social aspects--Yemen.
Water-supply, Rural--Economic aspects--Yemen.
Water-supply, Rural--Social aspects--Yemen.