Publisher
- Canada Centre for Mapping1
- GLIMS1
- Gap Analysis Program (U.S.)2
- Geological Survey (U.S.)26
- Instituto Nacional de Estadística, Geografía e Informática (Mexico)1
- National Atlas of the United States83
- U.S. Census Bureau. Geography Division1
- United States. Bureau of Transportation Statistics1
- World Data Center for Paleoclimatology5