Subject Region
United States
191
England
121
Great Britain
28
Developing countries
10
Mexico
7
Canada
6
Europe
5
Nigeria
5
California
4
Egypt
4
European Union countries
4
South Africa
4
Asia
3
Australia
3
Brazil
3
China
3
Espana
3
Germany
3
Malaysia
3
Rio de Janeiro
3
Spain
3
Central America
2
Colombia
2
India
2
Latin America
2
London
2
Maine
2
New Zealand
2
North America
2
Pennsylvania
2
Peru
2
Philadelphia
2
Vermont
2
Argentina
1
Baltimore
1
Boston
1
Boston (Mass.)
1
Burlington
1
Cairo
1
Cambodia
1
Connecticut
1
Developing Countries
1
East Asia
1
Ecuador
1
France
1
History
1
Italy
1
Lima
1
Maryland
1
Massachusetts
1
more ...