Subject Region
United States
162
Canada
14
European Union countries
11
Europe
7
Pennsylvania
7
Great Britain
6
New York (State)
5
Wisconsin
5
New York
3
Philadelphia
3
South Africa
3
Spain
3
West Virginia
3
Asia
2
California
2
Detroit
2
Italy
2
Michigan
2
Monongahela River Region (W. Va. and Pa.)
2
North America
2
Pacific States
2
Québec (Province)
2
Utah
2
Australia
1
China
1
England
1
Espana
1
France
1
Germany
1
Japan
1
Middle West
1
Monongahela River Region (W.Va. and Pa.)
1
Philadelphia (Pa.)
1
Scandinavia
1
Sweden
1