Region
Africa
1
Alabama
2
Asia
1
Austria
1
Belgium
1
Byzantine Empire
1
California
1
China
2
Cologne
1
Cologne (Germany)
1
Cuba
2
Developing countries
1
Egypt
1
England
5
Europa
1
Europe
14
France
3
Germany
4
Great Britain
2
India
1
Italy
2
Japan
3
Latin America
2
Leiden
1
Mexico
2
Middle East
1
Mississippi
2
Paris (France)
1
Rome
1
Sacramento
1
Soviet Union
1
Spain
2
Ukraine
1
United States
17
United states
1