Geographic Subject
United States
80
Germany
79
Europe
52
Soviet Union
52
India
42
China
30
France
29
Great Britain
27
Africa
18
Middle East
15
Asia
14
Indonesia
13
Japan
13
Latin America
13
Poland
12
Pakistan
11
Russia (Federation)
11
Turkey
11
Russia
10
Developing countries
9
Thailand
9
Czechoslovakia
7
Europe, Eastern
7
Italy
7
Austria
6
Cuba
6
Canada
5
Egypt
5
Iran
5
Israel
5
Jammu and Kashmir (India)
5
Mexico
5
Siberia (Russia)
5
South Africa
5
Spain
5
Yugoslavia
5
Africa, Southern
4
Arab countries
4
Argentina
4
Germany (West)
4
Islamic countries
4
Portugal
4
Rome
4
Africa, Sub-Saharan
3
Algeria
3
Asia, Southeastern
3
Bulgaria
3
Caribbean Area
3
Colombia
3
Communist countries
3
more ...