Region
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Caspian Sea Region
5
Cuba
5
Indonesia
5
Qatar
5
Asia
4
Daqing (Heilongjiang Sheng)
4
Gulf Coast (U.S.)
4
Libya
4
Pacific States
4
South America
4
Africa, North
3
Africa, Sub-Saharan
3
America
3
Arctic regions
3
Athabasca Tar Sands (Alta.)
3
California, Southern
3
Cook Inlet
3
East Asia
3
Equatorial Guinea
3
Europe, Eastern
3
Europe, Western
3
Galicia (Poland and Ukraine)
3
Guadalupe Region
3
Guadalupe-Nipomo Dunes National Wildlife Refuge (Calif.)
3
Guinea, Gulf of
3
Huasteca Region
3
Los Angeles
3
Maine
3
Middle West
3
Montana
3
Netherlands
3
New Jersey
3
Niger River Delta (Nigeria)
3
North Sea
3
Oil Creek Valley (Crawford County and Venango County, Pa.)
3
Pacific Area
3
South Africa
3
West (U.S.)
3
Africa, West
2
Algeria
2
Angola
2
Arctic Coast
2
Arctic Coast (Russia)
2
Asia, Central
2
Athabasca Tar Sands
2
Bahlāʼ
2
Bahlāʼ (Oman)
2
Baku
2
Bolivia
2
Canada, Western
2
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