1968. Paul Jacobs, Rebecca Barney, Len Kne, Ya Tao, and Dan Milz. A digitized version of Ian McHarg's original 1968 Ecological Study for the Twin Cities Metropolitan Area: Composite Intrinsic Suitability. These ma... University of Minnesota Digital Conservancy.
1880. Provides access to a digital collection of historical color fire insurance maps, real estate atlases, and similar land use maps for North America. ... Historical Information Gatherers, Inc.