Miền
United States
6
China
3
Developing countries
2
Islamic countries
2
Nebraska
2
Pakistan
2
Sandhills
2
Sandhills (Neb.)
2
Africa
1
Baltic Sea
1
Belarus
1
Canada
1
Carpathian Mountains Region
1
Central America
1
Chamberlain Farm
1
Chamberlain Farm (Me.)
1
East Asia
1
Effect of human beings on
1
Germany
1
Great Basin
1
Great Britain
1
Maine
1
Middle West
1
New England
1
New Mexico
1
North America
1
Polar regions
1
Portugal
1
South America
1
Sun
1
Sweden
1
Univers
1