Subject Region
United States
78
Developing countries
6
Great Britain
4
Europe
2
Africa, Sub-Saharan
1
Australia
1
California
1
Cost effectiveness
1
Cuba
1
Economic development
1
Environmental policy
1
Ethiopia
1
European Union countries
1
Germany
1
Ghana
1
Idaho
1
Netherlands
1
New Zealand
1
Pakistan
1
Saint Lucia
1
Volta, Lake
1