1998. U.S. Geological Survey and Minnesota DNR and Minnesota Department of Natural Resources (DNR). A digital raster graphic (DRG) is a scanned image of an U.S. Geological Survey (USGS) standard series topographic map, including all map collar inf...
1977. Wade; Cathey; Oldham. Projection: Lambert Conformal Conic Projection: Standard Parallels -76°40' and -79°20'; Series: USGS 1:250,000 Geologic Reconnaissance Series.
1956. Downloaded from CIA Flickr page: https://www.flickr.com/photos/ciagov/albums/72157674885572481/with/30252922504/; Series: CIA Declassified Maps.