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Subject
- Roads13
- World maps8
- Diplomatic and consular service, American7
- Humanitarian assistance7
- Time7
- United States. Department of State4
- Geology3
- Groundwater3
- Aquifers2
- Harbors2
- Landforms2
- Radioactive pollution of water2
- Uranium2
- World War, 1914-19182
- Agriculture1
- Cartography1
- Census districts1
- Dam failures1
- Electric power1
- Emergency management1