Geography
United States
36 results
Developing countries
22 results
Soviet Union
15 results
Europe, Eastern
5 results
Europe
4 results
Australia
3 results
China
3 results
Latin America
3 results
Middle East
3 results
Asia
2 results
Iran
2 results
Africa
1 results
Africa, West
1 results
Andes Region
1 results
Arab countries
1 results
Aswan High Dam (Egypt)
1 results
Atlantic Ocean
1 results
Bangladesh
1 results
Canada
1 results
Communist countries
1 results
Congo (Democratic Republic)
1 results
Europe de l'Est
1 results
European Economic Community countries
1 results
Germany (East)
1 results
Germany (West)
1 results
Israel
1 results
Mexico
1 results
Mexico,
1 results
Nasir Reservoir Region, Egypt and Sudan
1 results
North Atlantic Region
1 results
Pacific Area
1 results
URSS
1 results