1. Glacial map of North America Author/Creator: National Research Council (U.S.). Division of Earth Sciences Publication/Creation: New York : Geological Society of America, 1945 Resource Type: Map Edition: 1st edition. Access & Availability: Loading
2. Global GIS database. North America Publication/Creation: [Flagstaff. AZ] : USGS, [2003?] Resource Type: Map Edition: Data only version. Access & Availability: Loading